Initial commit

Signed-off-by: Mavridis Philippe <mavridisf@gmail.com>

1 files changed, 2071 insertions, 0 deletions

diff --git a/src/sqlite/expr.c b/src/sqlite/expr.c
new file mode 100644
index 0000000..c17676e
--- /dev/null
+++ b/src/sqlite/expr.c
@@ -0,0 +1,2071 @@
+/*
+** 2001 September 15
+**
+** The author disclaims copyright to this source code.  In place of
+** a legal notice, here is a blessing:
+**
+**    May you do good and not evil.
+**    May you find forgiveness for yourself and forgive others.
+**    May you share freely, never taking more than you give.
+**
+*************************************************************************
+** This file contains routines used for analyzing expressions and
+** for generating VDBE code that evaluates expressions in SQLite.
+**
+** $Id: expr.c,v 1.1.1.1 2006/02/03 20:35:12 hoganrobert Exp $
+*/
+#include "sqliteInt.h"
+#include <ctype.h>
+
+/*
+** Return the 'affinity' of the expression pExpr if any.
+**
+** If pExpr is a column, a reference to a column via an 'AS' alias,
+** or a sub-select with a column as the return value, then the 
+** affinity of that column is returned. Otherwise, 0x00 is returned,
+** indicating no affinity for the expression.
+**
+** i.e. the WHERE clause expresssions in the following statements all
+** have an affinity:
+**
+** CREATE TABLE t1(a);
+** SELECT * FROM t1 WHERE a;
+** SELECT a AS b FROM t1 WHERE b;
+** SELECT * FROM t1 WHERE (select a from t1);
+*/
+char sqlite3ExprAffinity(Expr *pExpr){
+  if( pExpr->op==TK_AS ){
+    return sqlite3ExprAffinity(pExpr->pLeft);
+  }
+  if( pExpr->op==TK_SELECT ){
+    return sqlite3ExprAffinity(pExpr->pSelect->pEList->a[0].pExpr);
+  }
+  return pExpr->affinity;
+}
+
+/*
+** Return the default collation sequence for the expression pExpr. If
+** there is no default collation type, return 0.
+*/
+CollSeq *sqlite3ExprCollSeq(Parse *pParse, Expr *pExpr){
+  CollSeq *pColl = 0;
+  if( pExpr ){
+    pColl = pExpr->pColl;
+    if( pExpr->op==TK_AS && !pColl ){
+      return sqlite3ExprCollSeq(pParse, pExpr->pLeft);
+    }
+  }
+  if( sqlite3CheckCollSeq(pParse, pColl) ){ 
+    pColl = 0;
+  }
+  return pColl;
+}
+
+/*
+** pExpr is an operand of a comparison operator.  aff2 is the
+** type affinity of the other operand.  This routine returns the
+** type affinity that should be used for the comparison operator.
+*/
+char sqlite3CompareAffinity(Expr *pExpr, char aff2){
+  char aff1 = sqlite3ExprAffinity(pExpr);
+  if( aff1 && aff2 ){
+    /* Both sides of the comparison are columns. If one has numeric or
+    ** integer affinity, use that. Otherwise use no affinity.
+    */
+    if( aff1==SQLITE_AFF_INTEGER || aff2==SQLITE_AFF_INTEGER ){
+      return SQLITE_AFF_INTEGER;
+    }else if( aff1==SQLITE_AFF_NUMERIC || aff2==SQLITE_AFF_NUMERIC ){
+      return SQLITE_AFF_NUMERIC;
+    }else{
+      return SQLITE_AFF_NONE;
+    }
+  }else if( !aff1 && !aff2 ){
+    /* Neither side of the comparison is a column.  Compare the
+    ** results directly.
+    */
+    /* return SQLITE_AFF_NUMERIC;  // Ticket #805 */
+    return SQLITE_AFF_NONE;
+  }else{
+    /* One side is a column, the other is not. Use the columns affinity. */
+    return (aff1 + aff2);
+  }
+}
+
+/*
+** pExpr is a comparison operator.  Return the type affinity that should
+** be applied to both operands prior to doing the comparison.
+*/
+static char comparisonAffinity(Expr *pExpr){
+  char aff;
+  assert( pExpr->op==TK_EQ || pExpr->op==TK_IN || pExpr->op==TK_LT ||
+          pExpr->op==TK_GT || pExpr->op==TK_GE || pExpr->op==TK_LE ||
+          pExpr->op==TK_NE );
+  assert( pExpr->pLeft );
+  aff = sqlite3ExprAffinity(pExpr->pLeft);
+  if( pExpr->pRight ){
+    aff = sqlite3CompareAffinity(pExpr->pRight, aff);
+  }
+  else if( pExpr->pSelect ){
+    aff = sqlite3CompareAffinity(pExpr->pSelect->pEList->a[0].pExpr, aff);
+  }
+  else if( !aff ){
+    aff = SQLITE_AFF_NUMERIC;
+  }
+  return aff;
+}
+
+/*
+** pExpr is a comparison expression, eg. '=', '<', IN(...) etc.
+** idx_affinity is the affinity of an indexed column. Return true
+** if the index with affinity idx_affinity may be used to implement
+** the comparison in pExpr.
+*/
+int sqlite3IndexAffinityOk(Expr *pExpr, char idx_affinity){
+  char aff = comparisonAffinity(pExpr);
+  return 
+    (aff==SQLITE_AFF_NONE) ||
+    (aff==SQLITE_AFF_NUMERIC && idx_affinity==SQLITE_AFF_INTEGER) ||
+    (aff==SQLITE_AFF_INTEGER && idx_affinity==SQLITE_AFF_NUMERIC) ||
+    (aff==idx_affinity);
+}
+
+/*
+** Return the P1 value that should be used for a binary comparison
+** opcode (OP_Eq, OP_Ge etc.) used to compare pExpr1 and pExpr2.
+** If jumpIfNull is true, then set the low byte of the returned
+** P1 value to tell the opcode to jump if either expression
+** evaluates to NULL.
+*/
+static int binaryCompareP1(Expr *pExpr1, Expr *pExpr2, int jumpIfNull){
+  char aff = sqlite3ExprAffinity(pExpr2);
+  return ((int)sqlite3CompareAffinity(pExpr1, aff))+(jumpIfNull?0x100:0);
+}
+
+/*
+** Return a pointer to the collation sequence that should be used by
+** a binary comparison operator comparing pLeft and pRight.
+**
+** If the left hand expression has a collating sequence type, then it is
+** used. Otherwise the collation sequence for the right hand expression
+** is used, or the default (BINARY) if neither expression has a collating
+** type.
+*/
+static CollSeq* binaryCompareCollSeq(Parse *pParse, Expr *pLeft, Expr *pRight){
+  CollSeq *pColl = sqlite3ExprCollSeq(pParse, pLeft);
+  if( !pColl ){
+    pColl = sqlite3ExprCollSeq(pParse, pRight);
+  }
+  return pColl;
+}
+
+/*
+** Generate code for a comparison operator.
+*/
+static int codeCompare(
+  Parse *pParse,    /* The parsing (and code generating) context */
+  Expr *pLeft,      /* The left operand */
+  Expr *pRight,     /* The right operand */
+  int opcode,       /* The comparison opcode */
+  int dest,         /* Jump here if true.  */
+  int jumpIfNull    /* If true, jump if either operand is NULL */
+){
+  int p1 = binaryCompareP1(pLeft, pRight, jumpIfNull);
+  CollSeq *p3 = binaryCompareCollSeq(pParse, pLeft, pRight);
+  return sqlite3VdbeOp3(pParse->pVdbe, opcode, p1, dest, (void*)p3, P3_COLLSEQ);
+}
+
+/*
+** Construct a new expression node and return a pointer to it.  Memory
+** for this node is obtained from sqliteMalloc().  The calling function
+** is responsible for making sure the node eventually gets freed.
+*/
+Expr *sqlite3Expr(int op, Expr *pLeft, Expr *pRight, const Token *pToken){
+  Expr *pNew;
+  pNew = sqliteMalloc( sizeof(Expr) );
+  if( pNew==0 ){
+    /* When malloc fails, delete pLeft and pRight. Expressions passed to 
+    ** this function must always be allocated with sqlite3Expr() for this 
+    ** reason. 
+    */
+    sqlite3ExprDelete(pLeft);
+    sqlite3ExprDelete(pRight);
+    return 0;
+  }
+  pNew->op = op;
+  pNew->pLeft = pLeft;
+  pNew->pRight = pRight;
+  pNew->iAgg = -1;
+  if( pToken ){
+    assert( pToken->dyn==0 );
+    pNew->span = pNew->token = *pToken;
+  }else if( pLeft && pRight ){
+    sqlite3ExprSpan(pNew, &pLeft->span, &pRight->span);
+  }
+  return pNew;
+}
+
+/*
+** When doing a nested parse, you can include terms in an expression
+** that look like this:   #0 #1 #2 ...  These terms refer to elements
+** on the stack.  "#0" (or just "#") means the top of the stack.
+** "#1" means the next down on the stack.  And so forth.  #-1 means
+** memory location 0.  #-2 means memory location 1.  And so forth.
+**
+** This routine is called by the parser to deal with on of those terms.
+** It immediately generates code to store the value in a memory location.
+** The returns an expression that will code to extract the value from
+** that memory location as needed.
+*/
+Expr *sqlite3RegisterExpr(Parse *pParse, Token *pToken){
+  Vdbe *v = pParse->pVdbe;
+  Expr *p;
+  int depth;
+  if( v==0 ) return 0;
+  if( pParse->nested==0 ){
+    sqlite3ErrorMsg(pParse, "near \"%T\": syntax error", pToken);
+    return 0;
+  }
+  p = sqlite3Expr(TK_REGISTER, 0, 0, pToken);
+  if( p==0 ){
+    return 0;  /* Malloc failed */
+  }
+  depth = atoi(&pToken->z[1]);
+  if( depth>=0 ){
+    p->iTable = pParse->nMem++;
+    sqlite3VdbeAddOp(v, OP_Dup, depth, 0);
+    sqlite3VdbeAddOp(v, OP_MemStore, p->iTable, 1);
+  }else{
+    p->iTable = -1-depth;
+  }
+  return p;
+}
+
+/*
+** Join two expressions using an AND operator.  If either expression is
+** NULL, then just return the other expression.
+*/
+Expr *sqlite3ExprAnd(Expr *pLeft, Expr *pRight){
+  if( pLeft==0 ){
+    return pRight;
+  }else if( pRight==0 ){
+    return pLeft;
+  }else{
+    return sqlite3Expr(TK_AND, pLeft, pRight, 0);
+  }
+}
+
+/*
+** Set the Expr.span field of the given expression to span all
+** text between the two given tokens.
+*/
+void sqlite3ExprSpan(Expr *pExpr, Token *pLeft, Token *pRight){
+  assert( pRight!=0 );
+  assert( pLeft!=0 );
+  if( !sqlite3_malloc_failed && pRight->z && pLeft->z ){
+    assert( pLeft->dyn==0 || pLeft->z[pLeft->n]==0 );
+    if( pLeft->dyn==0 && pRight->dyn==0 ){
+      pExpr->span.z = pLeft->z;
+      pExpr->span.n = pRight->n + (pRight->z - pLeft->z);
+    }else{
+      pExpr->span.z = 0;
+    }
+  }
+}
+
+/*
+** Construct a new expression node for a function with multiple
+** arguments.
+*/
+Expr *sqlite3ExprFunction(ExprList *pList, Token *pToken){
+  Expr *pNew;
+  pNew = sqliteMalloc( sizeof(Expr) );
+  if( pNew==0 ){
+    sqlite3ExprListDelete(pList); /* Avoid leaking memory when malloc fails */
+    return 0;
+  }
+  pNew->op = TK_FUNCTION;
+  pNew->pList = pList;
+  if( pToken ){
+    assert( pToken->dyn==0 );
+    pNew->token = *pToken;
+  }else{
+    pNew->token.z = 0;
+  }
+  pNew->span = pNew->token;
+  return pNew;
+}
+
+/*
+** Assign a variable number to an expression that encodes a wildcard
+** in the original SQL statement.  
+**
+** Wildcards consisting of a single "?" are assigned the next sequential
+** variable number.
+**
+** Wildcards of the form "?nnn" are assigned the number "nnn".  We make
+** sure "nnn" is not too be to avoid a denial of service attack when
+** the SQL statement comes from an external source.
+**
+** Wildcards of the form ":aaa" or "$aaa" are assigned the same number
+** as the previous instance of the same wildcard.  Or if this is the first
+** instance of the wildcard, the next sequenial variable number is
+** assigned.
+*/
+void sqlite3ExprAssignVarNumber(Parse *pParse, Expr *pExpr){
+  Token *pToken;
+  if( pExpr==0 ) return;
+  pToken = &pExpr->token;
+  assert( pToken->n>=1 );
+  assert( pToken->z!=0 );
+  assert( pToken->z[0]!=0 );
+  if( pToken->n==1 ){
+    /* Wildcard of the form "?".  Assign the next variable number */
+    pExpr->iTable = ++pParse->nVar;
+  }else if( pToken->z[0]=='?' ){
+    /* Wildcard of the form "?nnn".  Convert "nnn" to an integer and
+    ** use it as the variable number */
+    int i;
+    pExpr->iTable = i = atoi(&pToken->z[1]);
+    if( i<1 || i>SQLITE_MAX_VARIABLE_NUMBER ){
+      sqlite3ErrorMsg(pParse, "variable number must be between ?1 and ?%d",
+          SQLITE_MAX_VARIABLE_NUMBER);
+    }
+    if( i>pParse->nVar ){
+      pParse->nVar = i;
+    }
+  }else{
+    /* Wildcards of the form ":aaa" or "$aaa".  Reuse the same variable
+    ** number as the prior appearance of the same name, or if the name
+    ** has never appeared before, reuse the same variable number
+    */
+    int i, n;
+    n = pToken->n;
+    for(i=0; i<pParse->nVarExpr; i++){
+      Expr *pE;
+      if( (pE = pParse->apVarExpr[i])!=0
+          && pE->token.n==n
+          && memcmp(pE->token.z, pToken->z, n)==0 ){
+        pExpr->iTable = pE->iTable;
+        break;
+      }
+    }
+    if( i>=pParse->nVarExpr ){
+      pExpr->iTable = ++pParse->nVar;
+      if( pParse->nVarExpr>=pParse->nVarExprAlloc-1 ){
+        pParse->nVarExprAlloc += pParse->nVarExprAlloc + 10;
+        pParse->apVarExpr = sqliteRealloc(pParse->apVarExpr,
+                       pParse->nVarExprAlloc*sizeof(pParse->apVarExpr[0]) );
+      }
+      if( !sqlite3_malloc_failed ){
+        assert( pParse->apVarExpr!=0 );
+        pParse->apVarExpr[pParse->nVarExpr++] = pExpr;
+      }
+    }
+  } 
+}
+
+/*
+** Recursively delete an expression tree.
+*/
+void sqlite3ExprDelete(Expr *p){
+  if( p==0 ) return;
+  if( p->span.dyn ) sqliteFree((char*)p->span.z);
+  if( p->token.dyn ) sqliteFree((char*)p->token.z);
+  sqlite3ExprDelete(p->pLeft);
+  sqlite3ExprDelete(p->pRight);
+  sqlite3ExprListDelete(p->pList);
+  sqlite3SelectDelete(p->pSelect);
+  sqliteFree(p);
+}
+
+
+/*
+** The following group of routines make deep copies of expressions,
+** expression lists, ID lists, and select statements.  The copies can
+** be deleted (by being passed to their respective ...Delete() routines)
+** without effecting the originals.
+**
+** The expression list, ID, and source lists return by sqlite3ExprListDup(),
+** sqlite3IdListDup(), and sqlite3SrcListDup() can not be further expanded 
+** by subsequent calls to sqlite*ListAppend() routines.
+**
+** Any tables that the SrcList might point to are not duplicated.
+*/
+Expr *sqlite3ExprDup(Expr *p){
+  Expr *pNew;
+  if( p==0 ) return 0;
+  pNew = sqliteMallocRaw( sizeof(*p) );
+  if( pNew==0 ) return 0;
+  memcpy(pNew, p, sizeof(*pNew));
+  if( p->token.z!=0 ){
+    pNew->token.z = sqliteStrNDup(p->token.z, p->token.n);
+    pNew->token.dyn = 1;
+  }else{
+    assert( pNew->token.z==0 );
+  }
+  pNew->span.z = 0;
+  pNew->pLeft = sqlite3ExprDup(p->pLeft);
+  pNew->pRight = sqlite3ExprDup(p->pRight);
+  pNew->pList = sqlite3ExprListDup(p->pList);
+  pNew->pSelect = sqlite3SelectDup(p->pSelect);
+  pNew->pTab = p->pTab;
+  return pNew;
+}
+void sqlite3TokenCopy(Token *pTo, Token *pFrom){
+  if( pTo->dyn ) sqliteFree((char*)pTo->z);
+  if( pFrom->z ){
+    pTo->n = pFrom->n;
+    pTo->z = sqliteStrNDup(pFrom->z, pFrom->n);
+    pTo->dyn = 1;
+  }else{
+    pTo->z = 0;
+  }
+}
+ExprList *sqlite3ExprListDup(ExprList *p){
+  ExprList *pNew;
+  struct ExprList_item *pItem, *pOldItem;
+  int i;
+  if( p==0 ) return 0;
+  pNew = sqliteMalloc( sizeof(*pNew) );
+  if( pNew==0 ) return 0;
+  pNew->nExpr = pNew->nAlloc = p->nExpr;
+  pNew->a = pItem = sqliteMalloc( p->nExpr*sizeof(p->a[0]) );
+  if( pItem==0 ){
+    sqliteFree(pNew);
+    return 0;
+  } 
+  pOldItem = p->a;
+  for(i=0; i<p->nExpr; i++, pItem++, pOldItem++){
+    Expr *pNewExpr, *pOldExpr;
+    pItem->pExpr = pNewExpr = sqlite3ExprDup(pOldExpr = pOldItem->pExpr);
+    if( pOldExpr->span.z!=0 && pNewExpr ){
+      /* Always make a copy of the span for top-level expressions in the
+      ** expression list.  The logic in SELECT processing that determines
+      ** the names of columns in the result set needs this information */
+      sqlite3TokenCopy(&pNewExpr->span, &pOldExpr->span);
+    }
+    assert( pNewExpr==0 || pNewExpr->span.z!=0 
+            || pOldExpr->span.z==0 || sqlite3_malloc_failed );
+    pItem->zName = sqliteStrDup(pOldItem->zName);
+    pItem->sortOrder = pOldItem->sortOrder;
+    pItem->isAgg = pOldItem->isAgg;
+    pItem->done = 0;
+  }
+  return pNew;
+}
+
+/*
+** If cursors, triggers, views and subqueries are all omitted from
+** the build, then none of the following routines, except for 
+** sqlite3SelectDup(), can be called. sqlite3SelectDup() is sometimes
+** called with a NULL argument.
+*/
+#if !defined(SQLITE_OMIT_VIEW) || !defined(SQLITE_OMIT_TRIGGER) \
+ || !defined(SQLITE_OMIT_SUBQUERY)
+SrcList *sqlite3SrcListDup(SrcList *p){
+  SrcList *pNew;
+  int i;
+  int nByte;
+  if( p==0 ) return 0;
+  nByte = sizeof(*p) + (p->nSrc>0 ? sizeof(p->a[0]) * (p->nSrc-1) : 0);
+  pNew = sqliteMallocRaw( nByte );
+  if( pNew==0 ) return 0;
+  pNew->nSrc = pNew->nAlloc = p->nSrc;
+  for(i=0; i<p->nSrc; i++){
+    struct SrcList_item *pNewItem = &pNew->a[i];
+    struct SrcList_item *pOldItem = &p->a[i];
+    Table *pTab;
+    pNewItem->zDatabase = sqliteStrDup(pOldItem->zDatabase);
+    pNewItem->zName = sqliteStrDup(pOldItem->zName);
+    pNewItem->zAlias = sqliteStrDup(pOldItem->zAlias);
+    pNewItem->jointype = pOldItem->jointype;
+    pNewItem->iCursor = pOldItem->iCursor;
+    pTab = pNewItem->pTab = pOldItem->pTab;
+    if( pTab ){
+      pTab->nRef++;
+    }
+    pNewItem->pSelect = sqlite3SelectDup(pOldItem->pSelect);
+    pNewItem->pOn = sqlite3ExprDup(pOldItem->pOn);
+    pNewItem->pUsing = sqlite3IdListDup(pOldItem->pUsing);
+    pNewItem->colUsed = pOldItem->colUsed;
+  }
+  return pNew;
+}
+IdList *sqlite3IdListDup(IdList *p){
+  IdList *pNew;
+  int i;
+  if( p==0 ) return 0;
+  pNew = sqliteMallocRaw( sizeof(*pNew) );
+  if( pNew==0 ) return 0;
+  pNew->nId = pNew->nAlloc = p->nId;
+  pNew->a = sqliteMallocRaw( p->nId*sizeof(p->a[0]) );
+  if( pNew->a==0 ){
+    sqliteFree(pNew);
+    return 0;
+  }
+  for(i=0; i<p->nId; i++){
+    struct IdList_item *pNewItem = &pNew->a[i];
+    struct IdList_item *pOldItem = &p->a[i];
+    pNewItem->zName = sqliteStrDup(pOldItem->zName);
+    pNewItem->idx = pOldItem->idx;
+  }
+  return pNew;
+}
+Select *sqlite3SelectDup(Select *p){
+  Select *pNew;
+  if( p==0 ) return 0;
+  pNew = sqliteMallocRaw( sizeof(*p) );
+  if( pNew==0 ) return 0;
+  pNew->isDistinct = p->isDistinct;
+  pNew->pEList = sqlite3ExprListDup(p->pEList);
+  pNew->pSrc = sqlite3SrcListDup(p->pSrc);
+  pNew->pWhere = sqlite3ExprDup(p->pWhere);
+  pNew->pGroupBy = sqlite3ExprListDup(p->pGroupBy);
+  pNew->pHaving = sqlite3ExprDup(p->pHaving);
+  pNew->pOrderBy = sqlite3ExprListDup(p->pOrderBy);
+  pNew->op = p->op;
+  pNew->pPrior = sqlite3SelectDup(p->pPrior);
+  pNew->pLimit = sqlite3ExprDup(p->pLimit);
+  pNew->pOffset = sqlite3ExprDup(p->pOffset);
+  pNew->iLimit = -1;
+  pNew->iOffset = -1;
+  pNew->ppOpenTemp = 0;
+  pNew->isResolved = p->isResolved;
+  pNew->isAgg = p->isAgg;
+  return pNew;
+}
+#else
+Select *sqlite3SelectDup(Select *p){
+  assert( p==0 );
+  return 0;
+}
+#endif
+
+
+/*
+** Add a new element to the end of an expression list.  If pList is
+** initially NULL, then create a new expression list.
+*/
+ExprList *sqlite3ExprListAppend(ExprList *pList, Expr *pExpr, Token *pName){
+  if( pList==0 ){
+    pList = sqliteMalloc( sizeof(ExprList) );
+    if( pList==0 ){
+      goto no_mem;
+    }
+    assert( pList->nAlloc==0 );
+  }
+  if( pList->nAlloc<=pList->nExpr ){
+    struct ExprList_item *a;
+    int n = pList->nAlloc*2 + 4;
+    a = sqliteRealloc(pList->a, n*sizeof(pList->a[0]));
+    if( a==0 ){
+      goto no_mem;
+    }
+    pList->a = a;
+    pList->nAlloc = n;
+  }
+  assert( pList->a!=0 );
+  if( pExpr || pName ){
+    struct ExprList_item *pItem = &pList->a[pList->nExpr++];
+    memset(pItem, 0, sizeof(*pItem));
+    pItem->zName = sqlite3NameFromToken(pName);
+    pItem->pExpr = pExpr;
+  }
+  return pList;
+
+no_mem:     
+  /* Avoid leaking memory if malloc has failed. */
+  sqlite3ExprDelete(pExpr);
+  sqlite3ExprListDelete(pList);
+  return 0;
+}
+
+/*
+** Delete an entire expression list.
+*/
+void sqlite3ExprListDelete(ExprList *pList){
+  int i;
+  struct ExprList_item *pItem;
+  if( pList==0 ) return;
+  assert( pList->a!=0 || (pList->nExpr==0 && pList->nAlloc==0) );
+  assert( pList->nExpr<=pList->nAlloc );
+  for(pItem=pList->a, i=0; i<pList->nExpr; i++, pItem++){
+    sqlite3ExprDelete(pItem->pExpr);
+    sqliteFree(pItem->zName);
+  }
+  sqliteFree(pList->a);
+  sqliteFree(pList);
+}
+
+/*
+** Walk an expression tree.  Call xFunc for each node visited.
+**
+** The return value from xFunc determines whether the tree walk continues.
+** 0 means continue walking the tree.  1 means do not walk children
+** of the current node but continue with siblings.  2 means abandon
+** the tree walk completely.
+**
+** The return value from this routine is 1 to abandon the tree walk
+** and 0 to continue.
+*/
+static int walkExprList(ExprList *, int (*)(void *, Expr*), void *);
+static int walkExprTree(Expr *pExpr, int (*xFunc)(void*,Expr*), void *pArg){
+  int rc;
+  if( pExpr==0 ) return 0;
+  rc = (*xFunc)(pArg, pExpr);
+  if( rc==0 ){
+    if( walkExprTree(pExpr->pLeft, xFunc, pArg) ) return 1;
+    if( walkExprTree(pExpr->pRight, xFunc, pArg) ) return 1;
+    if( walkExprList(pExpr->pList, xFunc, pArg) ) return 1;
+  }
+  return rc>1;
+}
+
+/*
+** Call walkExprTree() for every expression in list p.
+*/
+static int walkExprList(ExprList *p, int (*xFunc)(void *, Expr*), void *pArg){
+  int i;
+  struct ExprList_item *pItem;
+  if( !p ) return 0;
+  for(i=p->nExpr, pItem=p->a; i>0; i--, pItem++){
+    if( walkExprTree(pItem->pExpr, xFunc, pArg) ) return 1;
+  }
+  return 0;
+}
+
+/*
+** Call walkExprTree() for every expression in Select p, not including
+** expressions that are part of sub-selects in any FROM clause or the LIMIT
+** or OFFSET expressions..
+*/
+static int walkSelectExpr(Select *p, int (*xFunc)(void *, Expr*), void *pArg){
+  walkExprList(p->pEList, xFunc, pArg);
+  walkExprTree(p->pWhere, xFunc, pArg);
+  walkExprList(p->pGroupBy, xFunc, pArg);
+  walkExprTree(p->pHaving, xFunc, pArg);
+  walkExprList(p->pOrderBy, xFunc, pArg);
+  return 0;
+}
+
+
+/*
+** This routine is designed as an xFunc for walkExprTree().
+**
+** pArg is really a pointer to an integer.  If we can tell by looking
+** at pExpr that the expression that contains pExpr is not a constant
+** expression, then set *pArg to 0 and return 2 to abandon the tree walk.
+** If pExpr does does not disqualify the expression from being a constant
+** then do nothing.
+**
+** After walking the whole tree, if no nodes are found that disqualify
+** the expression as constant, then we assume the whole expression
+** is constant.  See sqlite3ExprIsConstant() for additional information.
+*/
+static int exprNodeIsConstant(void *pArg, Expr *pExpr){
+  switch( pExpr->op ){
+    case TK_ID:
+    case TK_COLUMN:
+    case TK_DOT:
+    case TK_AGG_FUNCTION:
+    case TK_FUNCTION:
+#ifndef SQLITE_OMIT_SUBQUERY
+    case TK_SELECT:
+    case TK_EXISTS:
+#endif
+      *((int*)pArg) = 0;
+      return 2;
+    default:
+      return 0;
+  }
+}
+
+/*
+** Walk an expression tree.  Return 1 if the expression is constant
+** and 0 if it involves variables.
+**
+** For the purposes of this function, a double-quoted string (ex: "abc")
+** is considered a variable but a single-quoted string (ex: 'abc') is
+** a constant.
+*/
+int sqlite3ExprIsConstant(Expr *p){
+  int isConst = 1;
+  walkExprTree(p, exprNodeIsConstant, &isConst);
+  return isConst;
+}
+
+/*
+** If the expression p codes a constant integer that is small enough
+** to fit in a 32-bit integer, return 1 and put the value of the integer
+** in *pValue.  If the expression is not an integer or if it is too big
+** to fit in a signed 32-bit integer, return 0 and leave *pValue unchanged.
+*/
+int sqlite3ExprIsInteger(Expr *p, int *pValue){
+  switch( p->op ){
+    case TK_INTEGER: {
+      if( sqlite3GetInt32(p->token.z, pValue) ){
+        return 1;
+      }
+      break;
+    }
+    case TK_UPLUS: {
+      return sqlite3ExprIsInteger(p->pLeft, pValue);
+    }
+    case TK_UMINUS: {
+      int v;
+      if( sqlite3ExprIsInteger(p->pLeft, &v) ){
+        *pValue = -v;
+        return 1;
+      }
+      break;
+    }
+    default: break;
+  }
+  return 0;
+}
+
+/*
+** Return TRUE if the given string is a row-id column name.
+*/
+int sqlite3IsRowid(const char *z){
+  if( sqlite3StrICmp(z, "_ROWID_")==0 ) return 1;
+  if( sqlite3StrICmp(z, "ROWID")==0 ) return 1;
+  if( sqlite3StrICmp(z, "OID")==0 ) return 1;
+  return 0;
+}
+
+/*
+** Given the name of a column of the form X.Y.Z or Y.Z or just Z, look up
+** that name in the set of source tables in pSrcList and make the pExpr 
+** expression node refer back to that source column.  The following changes
+** are made to pExpr:
+**
+**    pExpr->iDb           Set the index in db->aDb[] of the database holding
+**                         the table.
+**    pExpr->iTable        Set to the cursor number for the table obtained
+**                         from pSrcList.
+**    pExpr->iColumn       Set to the column number within the table.
+**    pExpr->op            Set to TK_COLUMN.
+**    pExpr->pLeft         Any expression this points to is deleted
+**    pExpr->pRight        Any expression this points to is deleted.
+**
+** The pDbToken is the name of the database (the "X").  This value may be
+** NULL meaning that name is of the form Y.Z or Z.  Any available database
+** can be used.  The pTableToken is the name of the table (the "Y").  This
+** value can be NULL if pDbToken is also NULL.  If pTableToken is NULL it
+** means that the form of the name is Z and that columns from any table
+** can be used.
+**
+** If the name cannot be resolved unambiguously, leave an error message
+** in pParse and return non-zero.  Return zero on success.
+*/
+static int lookupName(
+  Parse *pParse,      /* The parsing context */
+  Token *pDbToken,     /* Name of the database containing table, or NULL */
+  Token *pTableToken,  /* Name of table containing column, or NULL */
+  Token *pColumnToken, /* Name of the column. */
+  NameContext *pNC,    /* The name context used to resolve the name */
+  Expr *pExpr          /* Make this EXPR node point to the selected column */
+){
+  char *zDb = 0;       /* Name of the database.  The "X" in X.Y.Z */
+  char *zTab = 0;      /* Name of the table.  The "Y" in X.Y.Z or Y.Z */
+  char *zCol = 0;      /* Name of the column.  The "Z" */
+  int i, j;            /* Loop counters */
+  int cnt = 0;         /* Number of matching column names */
+  int cntTab = 0;      /* Number of matching table names */
+  sqlite3 *db = pParse->db;  /* The database */
+  struct SrcList_item *pItem;       /* Use for looping over pSrcList items */
+  struct SrcList_item *pMatch = 0;  /* The matching pSrcList item */
+  NameContext *pTopNC = pNC;        /* First namecontext in the list */
+
+  assert( pColumnToken && pColumnToken->z ); /* The Z in X.Y.Z cannot be NULL */
+  zDb = sqlite3NameFromToken(pDbToken);
+  zTab = sqlite3NameFromToken(pTableToken);
+  zCol = sqlite3NameFromToken(pColumnToken);
+  if( sqlite3_malloc_failed ){
+    goto lookupname_end;
+  }
+
+  pExpr->iTable = -1;
+  while( pNC && cnt==0 ){
+    SrcList *pSrcList = pNC->pSrcList;
+    ExprList *pEList = pNC->pEList;
+
+    /* assert( zTab==0 || pEList==0 ); */
+    if( pSrcList ){
+      for(i=0, pItem=pSrcList->a; i<pSrcList->nSrc; i++, pItem++){
+        Table *pTab = pItem->pTab;
+        Column *pCol;
+  
+        if( pTab==0 ) continue;
+        assert( pTab->nCol>0 );
+        if( zTab ){
+          if( pItem->zAlias ){
+            char *zTabName = pItem->zAlias;
+            if( sqlite3StrICmp(zTabName, zTab)!=0 ) continue;
+          }else{
+            char *zTabName = pTab->zName;
+            if( zTabName==0 || sqlite3StrICmp(zTabName, zTab)!=0 ) continue;
+            if( zDb!=0 && sqlite3StrICmp(db->aDb[pTab->iDb].zName, zDb)!=0 ){
+              continue;
+            }
+          }
+        }
+        if( 0==(cntTab++) ){
+          pExpr->iTable = pItem->iCursor;
+          pExpr->iDb = pTab->iDb;
+          pMatch = pItem;
+        }
+        for(j=0, pCol=pTab->aCol; j<pTab->nCol; j++, pCol++){
+          if( sqlite3StrICmp(pCol->zName, zCol)==0 ){
+            IdList *pUsing;
+            cnt++;
+            pExpr->iTable = pItem->iCursor;
+            pMatch = pItem;
+            pExpr->iDb = pTab->iDb;
+            /* Substitute the rowid (column -1) for the INTEGER PRIMARY KEY */
+            pExpr->iColumn = j==pTab->iPKey ? -1 : j;
+            pExpr->affinity = pTab->aCol[j].affinity;
+            pExpr->pColl = pTab->aCol[j].pColl;
+            if( pItem->jointype & JT_NATURAL ){
+              /* If this match occurred in the left table of a natural join,
+              ** then skip the right table to avoid a duplicate match */
+              pItem++;
+              i++;
+            }
+            if( (pUsing = pItem->pUsing)!=0 ){
+              /* If this match occurs on a column that is in the USING clause
+              ** of a join, skip the search of the right table of the join
+              ** to avoid a duplicate match there. */
+              int k;
+              for(k=0; k<pUsing->nId; k++){
+                if( sqlite3StrICmp(pUsing->a[k].zName, zCol)==0 ){
+                  pItem++;
+                  i++;
+                  break;
+                }
+              }
+            }
+            break;
+          }
+        }
+      }
+    }
+
+#ifndef SQLITE_OMIT_TRIGGER
+    /* If we have not already resolved the name, then maybe 
+    ** it is a new.* or old.* trigger argument reference
+    */
+    if( zDb==0 && zTab!=0 && cnt==0 && pParse->trigStack!=0 ){
+      TriggerStack *pTriggerStack = pParse->trigStack;
+      Table *pTab = 0;
+      if( pTriggerStack->newIdx != -1 && sqlite3StrICmp("new", zTab) == 0 ){
+        pExpr->iTable = pTriggerStack->newIdx;
+        assert( pTriggerStack->pTab );
+        pTab = pTriggerStack->pTab;
+      }else if( pTriggerStack->oldIdx != -1 && sqlite3StrICmp("old", zTab)==0 ){
+        pExpr->iTable = pTriggerStack->oldIdx;
+        assert( pTriggerStack->pTab );
+        pTab = pTriggerStack->pTab;
+      }
+
+      if( pTab ){ 
+        int j;
+        Column *pCol = pTab->aCol;
+
+        pExpr->iDb = pTab->iDb;
+        cntTab++;
+        for(j=0; j < pTab->nCol; j++, pCol++) {
+          if( sqlite3StrICmp(pCol->zName, zCol)==0 ){
+            cnt++;
+            pExpr->iColumn = j==pTab->iPKey ? -1 : j;
+            pExpr->affinity = pTab->aCol[j].affinity;
+            pExpr->pColl = pTab->aCol[j].pColl;
+            pExpr->pTab = pTab;
+            break;
+          }
+        }
+      }
+    }
+#endif /* !defined(SQLITE_OMIT_TRIGGER) */
+
+    /*
+    ** Perhaps the name is a reference to the ROWID
+    */
+    if( cnt==0 && cntTab==1 && sqlite3IsRowid(zCol) ){
+      cnt = 1;
+      pExpr->iColumn = -1;
+      pExpr->affinity = SQLITE_AFF_INTEGER;
+    }
+
+    /*
+    ** If the input is of the form Z (not Y.Z or X.Y.Z) then the name Z
+    ** might refer to an result-set alias.  This happens, for example, when
+    ** we are resolving names in the WHERE clause of the following command:
+    **
+    **     SELECT a+b AS x FROM table WHERE x<10;
+    **
+    ** In cases like this, replace pExpr with a copy of the expression that
+    ** forms the result set entry ("a+b" in the example) and return immediately.
+    ** Note that the expression in the result set should have already been
+    ** resolved by the time the WHERE clause is resolved.
+    */
+    if( cnt==0 && pEList!=0 && zTab==0 ){
+      for(j=0; j<pEList->nExpr; j++){
+        char *zAs = pEList->a[j].zName;
+        if( zAs!=0 && sqlite3StrICmp(zAs, zCol)==0 ){
+          assert( pExpr->pLeft==0 && pExpr->pRight==0 );
+          pExpr->op = TK_AS;
+          pExpr->iColumn = j;
+          pExpr->pLeft = sqlite3ExprDup(pEList->a[j].pExpr);
+          cnt = 1;
+          assert( zTab==0 && zDb==0 );
+          goto lookupname_end_2;
+        }
+      } 
+    }
+
+    /* Advance to the next name context.  The loop will exit when either
+    ** we have a match (cnt>0) or when we run out of name contexts.
+    */
+    if( cnt==0 ){
+      pNC = pNC->pNext;
+    }
+  }
+
+  /*
+  ** If X and Y are NULL (in other words if only the column name Z is
+  ** supplied) and the value of Z is enclosed in double-quotes, then
+  ** Z is a string literal if it doesn't match any column names.  In that
+  ** case, we need to return right away and not make any changes to
+  ** pExpr.
+  **
+  ** Because no reference was made to outer contexts, the pNC->nRef
+  ** fields are not changed in any context.
+  */
+  if( cnt==0 && zTab==0 && pColumnToken->z[0]=='"' ){
+    sqliteFree(zCol);
+    return 0;
+  }
+
+  /*
+  ** cnt==0 means there was not match.  cnt>1 means there were two or
+  ** more matches.  Either way, we have an error.
+  */
+  if( cnt!=1 ){
+    char *z = 0;
+    char *zErr;
+    zErr = cnt==0 ? "no such column: %s" : "ambiguous column name: %s";
+    if( zDb ){
+      sqlite3SetString(&z, zDb, ".", zTab, ".", zCol, 0);
+    }else if( zTab ){
+      sqlite3SetString(&z, zTab, ".", zCol, 0);
+    }else{
+      z = sqliteStrDup(zCol);
+    }
+    sqlite3ErrorMsg(pParse, zErr, z);
+    sqliteFree(z);
+    pTopNC->nErr++;
+  }
+
+  /* If a column from a table in pSrcList is referenced, then record
+  ** this fact in the pSrcList.a[].colUsed bitmask.  Column 0 causes
+  ** bit 0 to be set.  Column 1 sets bit 1.  And so forth.  If the
+  ** column number is greater than the number of bits in the bitmask
+  ** then set the high-order bit of the bitmask.
+  */
+  if( pExpr->iColumn>=0 && pMatch!=0 ){
+    int n = pExpr->iColumn;
+    if( n>=sizeof(Bitmask)*8 ){
+      n = sizeof(Bitmask)*8-1;
+    }
+    assert( pMatch->iCursor==pExpr->iTable );
+    pMatch->colUsed |= 1<<n;
+  }
+
+lookupname_end:
+  /* Clean up and return
+  */
+  sqliteFree(zDb);
+  sqliteFree(zTab);
+  sqlite3ExprDelete(pExpr->pLeft);
+  pExpr->pLeft = 0;
+  sqlite3ExprDelete(pExpr->pRight);
+  pExpr->pRight = 0;
+  pExpr->op = TK_COLUMN;
+lookupname_end_2:
+  sqliteFree(zCol);
+  if( cnt==1 ){
+    assert( pNC!=0 );
+    sqlite3AuthRead(pParse, pExpr, pNC->pSrcList);
+    if( pMatch && !pMatch->pSelect ){
+      pExpr->pTab = pMatch->pTab;
+    }
+    /* Increment the nRef value on all name contexts from TopNC up to
+    ** the point where the name matched. */
+    for(;;){
+      assert( pTopNC!=0 );
+      pTopNC->nRef++;
+      if( pTopNC==pNC ) break;
+      pTopNC = pTopNC->pNext;
+    }
+    return 0;
+  } else {
+    return 1;
+  }
+}
+
+/*
+** This routine is designed as an xFunc for walkExprTree().
+**
+** Resolve symbolic names into TK_COLUMN operators for the current
+** node in the expression tree.  Return 0 to continue the search down
+** the tree or 2 to abort the tree walk.
+**
+** This routine also does error checking and name resolution for
+** function names.  The operator for aggregate functions is changed
+** to TK_AGG_FUNCTION.
+*/
+static int nameResolverStep(void *pArg, Expr *pExpr){
+  NameContext *pNC = (NameContext*)pArg;
+  SrcList *pSrcList;
+  Parse *pParse;
+
+  if( pExpr==0 ) return 1;
+  assert( pNC!=0 );
+  pSrcList = pNC->pSrcList;
+  pParse = pNC->pParse;
+
+  if( ExprHasAnyProperty(pExpr, EP_Resolved) ) return 1;
+  ExprSetProperty(pExpr, EP_Resolved);
+#ifndef NDEBUG
+  if( pSrcList ){
+    int i;
+    for(i=0; i<pSrcList->nSrc; i++){
+      assert( pSrcList->a[i].iCursor>=0 && pSrcList->a[i].iCursor<pParse->nTab);
+    }
+  }
+#endif
+  switch( pExpr->op ){
+    /* Double-quoted strings (ex: "abc") are used as identifiers if
+    ** possible.  Otherwise they remain as strings.  Single-quoted
+    ** strings (ex: 'abc') are always string literals.
+    */
+    case TK_STRING: {
+      if( pExpr->token.z[0]=='\'' ) break;
+      /* Fall thru into the TK_ID case if this is a double-quoted string */
+    }
+    /* A lone identifier is the name of a column.
+    */
+    case TK_ID: {
+      lookupName(pParse, 0, 0, &pExpr->token, pNC, pExpr);
+      return 1;
+    }
+  
+    /* A table name and column name:     ID.ID
+    ** Or a database, table and column:  ID.ID.ID
+    */
+    case TK_DOT: {
+      Token *pColumn;
+      Token *pTable;
+      Token *pDb;
+      Expr *pRight;
+
+      /* if( pSrcList==0 ) break; */
+      pRight = pExpr->pRight;
+      if( pRight->op==TK_ID ){
+        pDb = 0;
+        pTable = &pExpr->pLeft->token;
+        pColumn = &pRight->token;
+      }else{
+        assert( pRight->op==TK_DOT );
+        pDb = &pExpr->pLeft->token;
+        pTable = &pRight->pLeft->token;
+        pColumn = &pRight->pRight->token;
+      }
+      lookupName(pParse, pDb, pTable, pColumn, pNC, pExpr);
+      return 1;
+    }
+
+    /* Resolve function names
+    */
+    case TK_CONST_FUNC:
+    case TK_FUNCTION: {
+      ExprList *pList = pExpr->pList;    /* The argument list */
+      int n = pList ? pList->nExpr : 0;  /* Number of arguments */
+      int no_such_func = 0;       /* True if no such function exists */
+      int wrong_num_args = 0;     /* True if wrong number of arguments */
+      int is_agg = 0;             /* True if is an aggregate function */
+      int i;
+      int nId;                    /* Number of characters in function name */
+      const char *zId;            /* The function name. */
+      FuncDef *pDef;              /* Information about the function */
+      int enc = pParse->db->enc;  /* The database encoding */
+
+      zId = pExpr->token.z;
+      nId = pExpr->token.n;
+      pDef = sqlite3FindFunction(pParse->db, zId, nId, n, enc, 0);
+      if( pDef==0 ){
+        pDef = sqlite3FindFunction(pParse->db, zId, nId, -1, enc, 0);
+        if( pDef==0 ){
+          no_such_func = 1;
+        }else{
+          wrong_num_args = 1;
+        }
+      }else{
+        is_agg = pDef->xFunc==0;
+      }
+      if( is_agg && !pNC->allowAgg ){
+        sqlite3ErrorMsg(pParse, "misuse of aggregate function %.*s()", nId,zId);
+        pNC->nErr++;
+        is_agg = 0;
+      }else if( no_such_func ){
+        sqlite3ErrorMsg(pParse, "no such function: %.*s", nId, zId);
+        pNC->nErr++;
+      }else if( wrong_num_args ){
+        sqlite3ErrorMsg(pParse,"wrong number of arguments to function %.*s()",
+             nId, zId);
+        pNC->nErr++;
+      }
+      if( is_agg ){
+        pExpr->op = TK_AGG_FUNCTION;
+        pNC->hasAgg = 1;
+      }
+      if( is_agg ) pNC->allowAgg = 0;
+      for(i=0; pNC->nErr==0 && i<n; i++){
+        walkExprTree(pList->a[i].pExpr, nameResolverStep, pNC);
+      }
+      if( is_agg ) pNC->allowAgg = 1;
+      /* FIX ME:  Compute pExpr->affinity based on the expected return
+      ** type of the function 
+      */
+      return is_agg;
+    }
+#ifndef SQLITE_OMIT_SUBQUERY
+    case TK_SELECT:
+    case TK_EXISTS:
+#endif
+    case TK_IN: {
+      if( pExpr->pSelect ){
+        int nRef = pNC->nRef;
+        sqlite3SelectResolve(pParse, pExpr->pSelect, pNC);
+        assert( pNC->nRef>=nRef );
+        if( nRef!=pNC->nRef ){
+          ExprSetProperty(pExpr, EP_VarSelect);
+        }
+      }
+    }
+  }
+  return 0;
+}
+
+/*
+** This routine walks an expression tree and resolves references to
+** table columns.  Nodes of the form ID.ID or ID resolve into an
+** index to the table in the table list and a column offset.  The 
+** Expr.opcode for such nodes is changed to TK_COLUMN.  The Expr.iTable
+** value is changed to the index of the referenced table in pTabList
+** plus the "base" value.  The base value will ultimately become the
+** VDBE cursor number for a cursor that is pointing into the referenced
+** table.  The Expr.iColumn value is changed to the index of the column 
+** of the referenced table.  The Expr.iColumn value for the special
+** ROWID column is -1.  Any INTEGER PRIMARY KEY column is tried as an
+** alias for ROWID.
+**
+** Also resolve function names and check the functions for proper
+** usage.  Make sure all function names are recognized and all functions
+** have the correct number of arguments.  Leave an error message
+** in pParse->zErrMsg if anything is amiss.  Return the number of errors.
+**
+** If the expression contains aggregate functions then set the EP_Agg
+** property on the expression.
+*/
+int sqlite3ExprResolveNames(
+  NameContext *pNC,       /* Namespace to resolve expressions in. */
+  Expr *pExpr             /* The expression to be analyzed. */
+){
+  if( pExpr==0 ) return 0;
+  walkExprTree(pExpr, nameResolverStep, pNC);
+  if( pNC->nErr>0 ){
+    ExprSetProperty(pExpr, EP_Error);
+  }
+  return ExprHasProperty(pExpr, EP_Error);
+}
+
+/*
+** A pointer instance of this structure is used to pass information
+** through walkExprTree into codeSubqueryStep().
+*/
+typedef struct QueryCoder QueryCoder;
+struct QueryCoder {
+  Parse *pParse;       /* The parsing context */
+  NameContext *pNC;    /* Namespace of first enclosing query */
+};
+
+
+/*
+** Generate code for subqueries and IN operators.
+**
+** IN operators comes in two forms:
+**
+**           expr IN (exprlist)
+** and
+**           expr IN (SELECT ...)
+**
+** The first form is handled by creating a set holding the list
+** of allowed values.  The second form causes the SELECT to generate 
+** a temporary table.
+*/
+#ifndef SQLITE_OMIT_SUBQUERY
+void sqlite3CodeSubselect(Parse *pParse, Expr *pExpr){
+  int label = 0;                         /* Address after sub-select code */
+  Vdbe *v = sqlite3GetVdbe(pParse);
+  if( v==0 ) return;
+
+  /* If this is not a variable (correlated) select, then execute
+  ** it only once. Unless this is part of a trigger program. In
+  ** that case re-execute every time (this could be optimized).
+  */
+  if( !ExprHasAnyProperty(pExpr, EP_VarSelect) && !pParse->trigStack ){
+    int mem = pParse->nMem++;
+    sqlite3VdbeAddOp(v, OP_MemLoad, mem, 0);
+    label = sqlite3VdbeMakeLabel(v);
+    sqlite3VdbeAddOp(v, OP_If, 0, label);
+    sqlite3VdbeAddOp(v, OP_Integer, 1, 0);
+    sqlite3VdbeAddOp(v, OP_MemStore, mem, 1);
+  }
+
+  if( pExpr->pSelect ){
+    sqlite3VdbeAddOp(v, OP_AggContextPush, 0, 0);
+  }
+
+  switch( pExpr->op ){
+    case TK_IN: {
+      char affinity;
+      KeyInfo keyInfo;
+      int addr;        /* Address of OP_OpenTemp instruction */
+
+      affinity = sqlite3ExprAffinity(pExpr->pLeft);
+
+      /* Whether this is an 'x IN(SELECT...)' or an 'x IN(<exprlist>)'
+      ** expression it is handled the same way. A temporary table is 
+      ** filled with single-field index keys representing the results
+      ** from the SELECT or the <exprlist>.
+      **
+      ** If the 'x' expression is a column value, or the SELECT...
+      ** statement returns a column value, then the affinity of that
+      ** column is used to build the index keys. If both 'x' and the
+      ** SELECT... statement are columns, then numeric affinity is used
+      ** if either column has NUMERIC or INTEGER affinity. If neither
+      ** 'x' nor the SELECT... statement are columns, then numeric affinity
+      ** is used.
+      */
+      pExpr->iTable = pParse->nTab++;
+      addr = sqlite3VdbeAddOp(v, OP_OpenTemp, pExpr->iTable, 0);
+      memset(&keyInfo, 0, sizeof(keyInfo));
+      keyInfo.nField = 1;
+      sqlite3VdbeAddOp(v, OP_SetNumColumns, pExpr->iTable, 1);
+
+      if( pExpr->pSelect ){
+        /* Case 1:     expr IN (SELECT ...)
+        **
+        ** Generate code to write the results of the select into the temporary
+        ** table allocated and opened above.
+        */
+        int iParm = pExpr->iTable +  (((int)affinity)<<16);
+        ExprList *pEList;
+        assert( (pExpr->iTable&0x0000FFFF)==pExpr->iTable );
+        sqlite3Select(pParse, pExpr->pSelect, SRT_Set, iParm, 0, 0, 0, 0);
+        pEList = pExpr->pSelect->pEList;
+        if( pEList && pEList->nExpr>0 ){ 
+          keyInfo.aColl[0] = binaryCompareCollSeq(pParse, pExpr->pLeft,
+              pEList->a[0].pExpr);
+        }
+      }else if( pExpr->pList ){
+        /* Case 2:     expr IN (exprlist)
+        **
+	** For each expression, build an index key from the evaluation and
+        ** store it in the temporary table. If <expr> is a column, then use
+        ** that columns affinity when building index keys. If <expr> is not
+        ** a column, use numeric affinity.
+        */
+        int i;
+        if( !affinity ){
+          affinity = SQLITE_AFF_NUMERIC;
+        }
+        keyInfo.aColl[0] = pExpr->pLeft->pColl;
+
+        /* Loop through each expression in <exprlist>. */
+        for(i=0; i<pExpr->pList->nExpr; i++){
+          Expr *pE2 = pExpr->pList->a[i].pExpr;
+
+          /* Check that the expression is constant and valid. */
+          if( !sqlite3ExprIsConstant(pE2) ){
+            sqlite3ErrorMsg(pParse,
+              "right-hand side of IN operator must be constant");
+            return;
+          }
+
+          /* Evaluate the expression and insert it into the temp table */
+          sqlite3ExprCode(pParse, pE2);
+          sqlite3VdbeOp3(v, OP_MakeRecord, 1, 0, &affinity, 1);
+          sqlite3VdbeAddOp(v, OP_IdxInsert, pExpr->iTable, 0);
+        }
+      }
+      sqlite3VdbeChangeP3(v, addr, (void *)&keyInfo, P3_KEYINFO);
+      break;
+    }
+
+    case TK_EXISTS:
+    case TK_SELECT: {
+      /* This has to be a scalar SELECT.  Generate code to put the
+      ** value of this select in a memory cell and record the number
+      ** of the memory cell in iColumn.
+      */
+      int sop;
+      Select *pSel;
+
+      pExpr->iColumn = pParse->nMem++;
+      pSel = pExpr->pSelect;
+      if( pExpr->op==TK_SELECT ){
+        sop = SRT_Mem;
+      }else{
+        static const Token one = { "1", 0, 1 };
+        sop = SRT_Exists;
+        sqlite3ExprListDelete(pSel->pEList);
+        pSel->pEList = sqlite3ExprListAppend(0, 
+                          sqlite3Expr(TK_INTEGER, 0, 0, &one), 0);
+      }
+      sqlite3Select(pParse, pSel, sop, pExpr->iColumn, 0, 0, 0, 0);
+      break;
+    }
+  }
+
+  if( pExpr->pSelect ){
+    sqlite3VdbeAddOp(v, OP_AggContextPop, 0, 0);
+  }
+  if( label<0 ){
+    sqlite3VdbeResolveLabel(v, label);
+  }
+  return;
+}
+#endif /* SQLITE_OMIT_SUBQUERY */
+
+/*
+** Generate an instruction that will put the integer describe by
+** text z[0..n-1] on the stack.
+*/
+static void codeInteger(Vdbe *v, const char *z, int n){
+  int i;
+  if( sqlite3GetInt32(z, &i) ){
+    sqlite3VdbeAddOp(v, OP_Integer, i, 0);
+  }else if( sqlite3FitsIn64Bits(z) ){
+    sqlite3VdbeOp3(v, OP_Integer, 0, 0, z, n);
+  }else{
+    sqlite3VdbeOp3(v, OP_Real, 0, 0, z, n);
+  }
+}
+
+/*
+** Generate code into the current Vdbe to evaluate the given
+** expression and leave the result on the top of stack.
+**
+** This code depends on the fact that certain token values (ex: TK_EQ)
+** are the same as opcode values (ex: OP_Eq) that implement the corresponding
+** operation.  Special comments in vdbe.c and the mkopcodeh.awk script in
+** the make process cause these values to align.  Assert()s in the code
+** below verify that the numbers are aligned correctly.
+*/
+void sqlite3ExprCode(Parse *pParse, Expr *pExpr){
+  Vdbe *v = pParse->pVdbe;
+  int op;
+  if( v==0 ) return;
+  if( pExpr==0 ){
+    sqlite3VdbeAddOp(v, OP_Null, 0, 0);
+    return;
+  }
+  op = pExpr->op;
+  switch( op ){
+    case TK_COLUMN: {
+      if( !pParse->fillAgg && pExpr->iAgg>=0 ){
+        sqlite3VdbeAddOp(v, OP_AggGet, pExpr->iAggCtx, pExpr->iAgg);
+      }else if( pExpr->iColumn>=0 ){
+        sqlite3VdbeAddOp(v, OP_Column, pExpr->iTable, pExpr->iColumn);
+        sqlite3ColumnDefault(v, pExpr->pTab, pExpr->iColumn);
+      }else{
+        sqlite3VdbeAddOp(v, OP_Rowid, pExpr->iTable, 0);
+      }
+      break;
+    }
+    case TK_INTEGER: {
+      codeInteger(v, pExpr->token.z, pExpr->token.n);
+      break;
+    }
+    case TK_FLOAT:
+    case TK_STRING: {
+      assert( TK_FLOAT==OP_Real );
+      assert( TK_STRING==OP_String8 );
+      sqlite3VdbeOp3(v, op, 0, 0, pExpr->token.z, pExpr->token.n);
+      sqlite3VdbeDequoteP3(v, -1);
+      break;
+    }
+    case TK_NULL: {
+      sqlite3VdbeAddOp(v, OP_Null, 0, 0);
+      break;
+    }
+#ifndef SQLITE_OMIT_BLOB_LITERAL
+    case TK_BLOB: {
+      assert( TK_BLOB==OP_HexBlob );
+      sqlite3VdbeOp3(v, op, 0, 0, pExpr->token.z+1, pExpr->token.n-1);
+      sqlite3VdbeDequoteP3(v, -1);
+      break;
+    }
+#endif
+    case TK_VARIABLE: {
+      sqlite3VdbeAddOp(v, OP_Variable, pExpr->iTable, 0);
+      if( pExpr->token.n>1 ){
+        sqlite3VdbeChangeP3(v, -1, pExpr->token.z, pExpr->token.n);
+      }
+      break;
+    }
+    case TK_REGISTER: {
+      sqlite3VdbeAddOp(v, OP_MemLoad, pExpr->iTable, 0);
+      break;
+    }
+    case TK_LT:
+    case TK_LE:
+    case TK_GT:
+    case TK_GE:
+    case TK_NE:
+    case TK_EQ: {
+      assert( TK_LT==OP_Lt );
+      assert( TK_LE==OP_Le );
+      assert( TK_GT==OP_Gt );
+      assert( TK_GE==OP_Ge );
+      assert( TK_EQ==OP_Eq );
+      assert( TK_NE==OP_Ne );
+      sqlite3ExprCode(pParse, pExpr->pLeft);
+      sqlite3ExprCode(pParse, pExpr->pRight);
+      codeCompare(pParse, pExpr->pLeft, pExpr->pRight, op, 0, 0);
+      break;
+    }
+    case TK_AND:
+    case TK_OR:
+    case TK_PLUS:
+    case TK_STAR:
+    case TK_MINUS:
+    case TK_REM:
+    case TK_BITAND:
+    case TK_BITOR:
+    case TK_SLASH:
+    case TK_LSHIFT:
+    case TK_RSHIFT: 
+    case TK_CONCAT: {
+      assert( TK_AND==OP_And );
+      assert( TK_OR==OP_Or );
+      assert( TK_PLUS==OP_Add );
+      assert( TK_MINUS==OP_Subtract );
+      assert( TK_REM==OP_Remainder );
+      assert( TK_BITAND==OP_BitAnd );
+      assert( TK_BITOR==OP_BitOr );
+      assert( TK_SLASH==OP_Divide );
+      assert( TK_LSHIFT==OP_ShiftLeft );
+      assert( TK_RSHIFT==OP_ShiftRight );
+      assert( TK_CONCAT==OP_Concat );
+      sqlite3ExprCode(pParse, pExpr->pLeft);
+      sqlite3ExprCode(pParse, pExpr->pRight);
+      sqlite3VdbeAddOp(v, op, 0, 0);
+      break;
+    }
+    case TK_UMINUS: {
+      Expr *pLeft = pExpr->pLeft;
+      assert( pLeft );
+      if( pLeft->op==TK_FLOAT || pLeft->op==TK_INTEGER ){
+        Token *p = &pLeft->token;
+        char *z = sqliteMalloc( p->n + 2 );
+        sprintf(z, "-%.*s", p->n, p->z);
+        if( pLeft->op==TK_FLOAT ){
+          sqlite3VdbeOp3(v, OP_Real, 0, 0, z, p->n+1);
+        }else{
+          codeInteger(v, z, p->n+1);
+        }
+        sqliteFree(z);
+        break;
+      }
+      /* Fall through into TK_NOT */
+    }
+    case TK_BITNOT:
+    case TK_NOT: {
+      assert( TK_BITNOT==OP_BitNot );
+      assert( TK_NOT==OP_Not );
+      sqlite3ExprCode(pParse, pExpr->pLeft);
+      sqlite3VdbeAddOp(v, op, 0, 0);
+      break;
+    }
+    case TK_ISNULL:
+    case TK_NOTNULL: {
+      int dest;
+      assert( TK_ISNULL==OP_IsNull );
+      assert( TK_NOTNULL==OP_NotNull );
+      sqlite3VdbeAddOp(v, OP_Integer, 1, 0);
+      sqlite3ExprCode(pParse, pExpr->pLeft);
+      dest = sqlite3VdbeCurrentAddr(v) + 2;
+      sqlite3VdbeAddOp(v, op, 1, dest);
+      sqlite3VdbeAddOp(v, OP_AddImm, -1, 0);
+      break;
+    }
+    case TK_AGG_FUNCTION: {
+      sqlite3VdbeAddOp(v, OP_AggGet, 0, pExpr->iAgg);
+      break;
+    }
+    case TK_CONST_FUNC:
+    case TK_FUNCTION: {
+      ExprList *pList = pExpr->pList;
+      int nExpr = pList ? pList->nExpr : 0;
+      FuncDef *pDef;
+      int nId;
+      const char *zId;
+      int p2 = 0;
+      int i;
+      u8 enc = pParse->db->enc;
+      CollSeq *pColl = 0;
+      zId = pExpr->token.z;
+      nId = pExpr->token.n;
+      pDef = sqlite3FindFunction(pParse->db, zId, nId, nExpr, enc, 0);
+      assert( pDef!=0 );
+      nExpr = sqlite3ExprCodeExprList(pParse, pList);
+      for(i=0; i<nExpr && i<32; i++){
+        if( sqlite3ExprIsConstant(pList->a[i].pExpr) ){
+          p2 |= (1<<i);
+        }
+        if( pDef->needCollSeq && !pColl ){
+          pColl = sqlite3ExprCollSeq(pParse, pList->a[i].pExpr);
+        }
+      }
+      if( pDef->needCollSeq ){
+        if( !pColl ) pColl = pParse->db->pDfltColl; 
+        sqlite3VdbeOp3(v, OP_CollSeq, 0, 0, (char *)pColl, P3_COLLSEQ);
+      }
+      sqlite3VdbeOp3(v, OP_Function, nExpr, p2, (char*)pDef, P3_FUNCDEF);
+      break;
+    }
+#ifndef SQLITE_OMIT_SUBQUERY
+    case TK_EXISTS:
+    case TK_SELECT: {
+      sqlite3CodeSubselect(pParse, pExpr);
+      sqlite3VdbeAddOp(v, OP_MemLoad, pExpr->iColumn, 0);
+      VdbeComment((v, "# load subquery result"));
+      break;
+    }
+    case TK_IN: {
+      int addr;
+      char affinity;
+      sqlite3CodeSubselect(pParse, pExpr);
+
+      /* Figure out the affinity to use to create a key from the results
+      ** of the expression. affinityStr stores a static string suitable for
+      ** P3 of OP_MakeRecord.
+      */
+      affinity = comparisonAffinity(pExpr);
+
+      sqlite3VdbeAddOp(v, OP_Integer, 1, 0);
+
+      /* Code the <expr> from "<expr> IN (...)". The temporary table
+      ** pExpr->iTable contains the values that make up the (...) set.
+      */
+      sqlite3ExprCode(pParse, pExpr->pLeft);
+      addr = sqlite3VdbeCurrentAddr(v);
+      sqlite3VdbeAddOp(v, OP_NotNull, -1, addr+4);            /* addr + 0 */
+      sqlite3VdbeAddOp(v, OP_Pop, 2, 0);
+      sqlite3VdbeAddOp(v, OP_Null, 0, 0);
+      sqlite3VdbeAddOp(v, OP_Goto, 0, addr+7);
+      sqlite3VdbeOp3(v, OP_MakeRecord, 1, 0, &affinity, 1);   /* addr + 4 */
+      sqlite3VdbeAddOp(v, OP_Found, pExpr->iTable, addr+7);
+      sqlite3VdbeAddOp(v, OP_AddImm, -1, 0);                  /* addr + 6 */
+
+      break;
+    }
+#endif
+    case TK_BETWEEN: {
+      Expr *pLeft = pExpr->pLeft;
+      struct ExprList_item *pLItem = pExpr->pList->a;
+      Expr *pRight = pLItem->pExpr;
+      sqlite3ExprCode(pParse, pLeft);
+      sqlite3VdbeAddOp(v, OP_Dup, 0, 0);
+      sqlite3ExprCode(pParse, pRight);
+      codeCompare(pParse, pLeft, pRight, OP_Ge, 0, 0);
+      sqlite3VdbeAddOp(v, OP_Pull, 1, 0);
+      pLItem++;
+      pRight = pLItem->pExpr;
+      sqlite3ExprCode(pParse, pRight);
+      codeCompare(pParse, pLeft, pRight, OP_Le, 0, 0);
+      sqlite3VdbeAddOp(v, OP_And, 0, 0);
+      break;
+    }
+    case TK_UPLUS:
+    case TK_AS: {
+      sqlite3ExprCode(pParse, pExpr->pLeft);
+      break;
+    }
+    case TK_CASE: {
+      int expr_end_label;
+      int jumpInst;
+      int addr;
+      int nExpr;
+      int i;
+      ExprList *pEList;
+      struct ExprList_item *aListelem;
+
+      assert(pExpr->pList);
+      assert((pExpr->pList->nExpr % 2) == 0);
+      assert(pExpr->pList->nExpr > 0);
+      pEList = pExpr->pList;
+      aListelem = pEList->a;
+      nExpr = pEList->nExpr;
+      expr_end_label = sqlite3VdbeMakeLabel(v);
+      if( pExpr->pLeft ){
+        sqlite3ExprCode(pParse, pExpr->pLeft);
+      }
+      for(i=0; i<nExpr; i=i+2){
+        sqlite3ExprCode(pParse, aListelem[i].pExpr);
+        if( pExpr->pLeft ){
+          sqlite3VdbeAddOp(v, OP_Dup, 1, 1);
+          jumpInst = codeCompare(pParse, pExpr->pLeft, aListelem[i].pExpr,
+                                 OP_Ne, 0, 1);
+          sqlite3VdbeAddOp(v, OP_Pop, 1, 0);
+        }else{
+          jumpInst = sqlite3VdbeAddOp(v, OP_IfNot, 1, 0);
+        }
+        sqlite3ExprCode(pParse, aListelem[i+1].pExpr);
+        sqlite3VdbeAddOp(v, OP_Goto, 0, expr_end_label);
+        addr = sqlite3VdbeCurrentAddr(v);
+        sqlite3VdbeChangeP2(v, jumpInst, addr);
+      }
+      if( pExpr->pLeft ){
+        sqlite3VdbeAddOp(v, OP_Pop, 1, 0);
+      }
+      if( pExpr->pRight ){
+        sqlite3ExprCode(pParse, pExpr->pRight);
+      }else{
+        sqlite3VdbeAddOp(v, OP_Null, 0, 0);
+      }
+      sqlite3VdbeResolveLabel(v, expr_end_label);
+      break;
+    }
+#ifndef SQLITE_OMIT_TRIGGER
+    case TK_RAISE: {
+      if( !pParse->trigStack ){
+        sqlite3ErrorMsg(pParse,
+                       "RAISE() may only be used within a trigger-program");
+	return;
+      }
+      if( pExpr->iColumn!=OE_Ignore ){
+         assert( pExpr->iColumn==OE_Rollback ||
+                 pExpr->iColumn == OE_Abort ||
+                 pExpr->iColumn == OE_Fail );
+         sqlite3VdbeOp3(v, OP_Halt, SQLITE_CONSTRAINT, pExpr->iColumn,
+                        pExpr->token.z, pExpr->token.n);
+         sqlite3VdbeDequoteP3(v, -1);
+      } else {
+         assert( pExpr->iColumn == OE_Ignore );
+         sqlite3VdbeAddOp(v, OP_ContextPop, 0, 0);
+         sqlite3VdbeAddOp(v, OP_Goto, 0, pParse->trigStack->ignoreJump);
+         VdbeComment((v, "# raise(IGNORE)"));
+      }
+    }
+#endif
+    break;
+  }
+}
+
+#ifndef SQLITE_OMIT_TRIGGER
+/*
+** Generate code that evalutes the given expression and leaves the result
+** on the stack.  See also sqlite3ExprCode().
+**
+** This routine might also cache the result and modify the pExpr tree
+** so that it will make use of the cached result on subsequent evaluations
+** rather than evaluate the whole expression again.  Trivial expressions are
+** not cached.  If the expression is cached, its result is stored in a 
+** memory location.
+*/
+void sqlite3ExprCodeAndCache(Parse *pParse, Expr *pExpr){
+  Vdbe *v = pParse->pVdbe;
+  int iMem;
+  int addr1, addr2;
+  if( v==0 ) return;
+  addr1 = sqlite3VdbeCurrentAddr(v);
+  sqlite3ExprCode(pParse, pExpr);
+  addr2 = sqlite3VdbeCurrentAddr(v);
+  if( addr2>addr1+1 || sqlite3VdbeGetOp(v, addr1)->opcode==OP_Function ){
+    iMem = pExpr->iTable = pParse->nMem++;
+    sqlite3VdbeAddOp(v, OP_MemStore, iMem, 0);
+    pExpr->op = TK_REGISTER;
+  }
+}
+#endif
+
+/*
+** Generate code that pushes the value of every element of the given
+** expression list onto the stack.
+**
+** Return the number of elements pushed onto the stack.
+*/
+int sqlite3ExprCodeExprList(
+  Parse *pParse,     /* Parsing context */
+  ExprList *pList    /* The expression list to be coded */
+){
+  struct ExprList_item *pItem;
+  int i, n;
+  Vdbe *v;
+  if( pList==0 ) return 0;
+  v = sqlite3GetVdbe(pParse);
+  n = pList->nExpr;
+  for(pItem=pList->a, i=0; i<n; i++, pItem++){
+    sqlite3ExprCode(pParse, pItem->pExpr);
+  }
+  return n;
+}
+
+/*
+** Generate code for a boolean expression such that a jump is made
+** to the label "dest" if the expression is true but execution
+** continues straight thru if the expression is false.
+**
+** If the expression evaluates to NULL (neither true nor false), then
+** take the jump if the jumpIfNull flag is true.
+**
+** This code depends on the fact that certain token values (ex: TK_EQ)
+** are the same as opcode values (ex: OP_Eq) that implement the corresponding
+** operation.  Special comments in vdbe.c and the mkopcodeh.awk script in
+** the make process cause these values to align.  Assert()s in the code
+** below verify that the numbers are aligned correctly.
+*/
+void sqlite3ExprIfTrue(Parse *pParse, Expr *pExpr, int dest, int jumpIfNull){
+  Vdbe *v = pParse->pVdbe;
+  int op = 0;
+  if( v==0 || pExpr==0 ) return;
+  op = pExpr->op;
+  switch( op ){
+    case TK_AND: {
+      int d2 = sqlite3VdbeMakeLabel(v);
+      sqlite3ExprIfFalse(pParse, pExpr->pLeft, d2, !jumpIfNull);
+      sqlite3ExprIfTrue(pParse, pExpr->pRight, dest, jumpIfNull);
+      sqlite3VdbeResolveLabel(v, d2);
+      break;
+    }
+    case TK_OR: {
+      sqlite3ExprIfTrue(pParse, pExpr->pLeft, dest, jumpIfNull);
+      sqlite3ExprIfTrue(pParse, pExpr->pRight, dest, jumpIfNull);
+      break;
+    }
+    case TK_NOT: {
+      sqlite3ExprIfFalse(pParse, pExpr->pLeft, dest, jumpIfNull);
+      break;
+    }
+    case TK_LT:
+    case TK_LE:
+    case TK_GT:
+    case TK_GE:
+    case TK_NE:
+    case TK_EQ: {
+      assert( TK_LT==OP_Lt );
+      assert( TK_LE==OP_Le );
+      assert( TK_GT==OP_Gt );
+      assert( TK_GE==OP_Ge );
+      assert( TK_EQ==OP_Eq );
+      assert( TK_NE==OP_Ne );
+      sqlite3ExprCode(pParse, pExpr->pLeft);
+      sqlite3ExprCode(pParse, pExpr->pRight);
+      codeCompare(pParse, pExpr->pLeft, pExpr->pRight, op, dest, jumpIfNull);
+      break;
+    }
+    case TK_ISNULL:
+    case TK_NOTNULL: {
+      assert( TK_ISNULL==OP_IsNull );
+      assert( TK_NOTNULL==OP_NotNull );
+      sqlite3ExprCode(pParse, pExpr->pLeft);
+      sqlite3VdbeAddOp(v, op, 1, dest);
+      break;
+    }
+    case TK_BETWEEN: {
+      /* The expression "x BETWEEN y AND z" is implemented as:
+      **
+      ** 1 IF (x < y) GOTO 3
+      ** 2 IF (x <= z) GOTO <dest>
+      ** 3 ...
+      */
+      int addr;
+      Expr *pLeft = pExpr->pLeft;
+      Expr *pRight = pExpr->pList->a[0].pExpr;
+      sqlite3ExprCode(pParse, pLeft);
+      sqlite3VdbeAddOp(v, OP_Dup, 0, 0);
+      sqlite3ExprCode(pParse, pRight);
+      addr = codeCompare(pParse, pLeft, pRight, OP_Lt, 0, !jumpIfNull);
+
+      pRight = pExpr->pList->a[1].pExpr;
+      sqlite3ExprCode(pParse, pRight);
+      codeCompare(pParse, pLeft, pRight, OP_Le, dest, jumpIfNull);
+
+      sqlite3VdbeAddOp(v, OP_Integer, 0, 0);
+      sqlite3VdbeChangeP2(v, addr, sqlite3VdbeCurrentAddr(v));
+      sqlite3VdbeAddOp(v, OP_Pop, 1, 0);
+      break;
+    }
+    default: {
+      sqlite3ExprCode(pParse, pExpr);
+      sqlite3VdbeAddOp(v, OP_If, jumpIfNull, dest);
+      break;
+    }
+  }
+}
+
+/*
+** Generate code for a boolean expression such that a jump is made
+** to the label "dest" if the expression is false but execution
+** continues straight thru if the expression is true.
+**
+** If the expression evaluates to NULL (neither true nor false) then
+** jump if jumpIfNull is true or fall through if jumpIfNull is false.
+*/
+void sqlite3ExprIfFalse(Parse *pParse, Expr *pExpr, int dest, int jumpIfNull){
+  Vdbe *v = pParse->pVdbe;
+  int op = 0;
+  if( v==0 || pExpr==0 ) return;
+
+  /* The value of pExpr->op and op are related as follows:
+  **
+  **       pExpr->op            op
+  **       ---------          ----------
+  **       TK_ISNULL          OP_NotNull
+  **       TK_NOTNULL         OP_IsNull
+  **       TK_NE              OP_Eq
+  **       TK_EQ              OP_Ne
+  **       TK_GT              OP_Le
+  **       TK_LE              OP_Gt
+  **       TK_GE              OP_Lt
+  **       TK_LT              OP_Ge
+  **
+  ** For other values of pExpr->op, op is undefined and unused.
+  ** The value of TK_ and OP_ constants are arranged such that we
+  ** can compute the mapping above using the following expression.
+  ** Assert()s verify that the computation is correct.
+  */
+  op = ((pExpr->op+(TK_ISNULL&1))^1)-(TK_ISNULL&1);
+
+  /* Verify correct alignment of TK_ and OP_ constants
+  */
+  assert( pExpr->op!=TK_ISNULL || op==OP_NotNull );
+  assert( pExpr->op!=TK_NOTNULL || op==OP_IsNull );
+  assert( pExpr->op!=TK_NE || op==OP_Eq );
+  assert( pExpr->op!=TK_EQ || op==OP_Ne );
+  assert( pExpr->op!=TK_LT || op==OP_Ge );
+  assert( pExpr->op!=TK_LE || op==OP_Gt );
+  assert( pExpr->op!=TK_GT || op==OP_Le );
+  assert( pExpr->op!=TK_GE || op==OP_Lt );
+
+  switch( pExpr->op ){
+    case TK_AND: {
+      sqlite3ExprIfFalse(pParse, pExpr->pLeft, dest, jumpIfNull);
+      sqlite3ExprIfFalse(pParse, pExpr->pRight, dest, jumpIfNull);
+      break;
+    }
+    case TK_OR: {
+      int d2 = sqlite3VdbeMakeLabel(v);
+      sqlite3ExprIfTrue(pParse, pExpr->pLeft, d2, !jumpIfNull);
+      sqlite3ExprIfFalse(pParse, pExpr->pRight, dest, jumpIfNull);
+      sqlite3VdbeResolveLabel(v, d2);
+      break;
+    }
+    case TK_NOT: {
+      sqlite3ExprIfTrue(pParse, pExpr->pLeft, dest, jumpIfNull);
+      break;
+    }
+    case TK_LT:
+    case TK_LE:
+    case TK_GT:
+    case TK_GE:
+    case TK_NE:
+    case TK_EQ: {
+      sqlite3ExprCode(pParse, pExpr->pLeft);
+      sqlite3ExprCode(pParse, pExpr->pRight);
+      codeCompare(pParse, pExpr->pLeft, pExpr->pRight, op, dest, jumpIfNull);
+      break;
+    }
+    case TK_ISNULL:
+    case TK_NOTNULL: {
+      sqlite3ExprCode(pParse, pExpr->pLeft);
+      sqlite3VdbeAddOp(v, op, 1, dest);
+      break;
+    }
+    case TK_BETWEEN: {
+      /* The expression is "x BETWEEN y AND z". It is implemented as:
+      **
+      ** 1 IF (x >= y) GOTO 3
+      ** 2 GOTO <dest>
+      ** 3 IF (x > z) GOTO <dest>
+      */
+      int addr;
+      Expr *pLeft = pExpr->pLeft;
+      Expr *pRight = pExpr->pList->a[0].pExpr;
+      sqlite3ExprCode(pParse, pLeft);
+      sqlite3VdbeAddOp(v, OP_Dup, 0, 0);
+      sqlite3ExprCode(pParse, pRight);
+      addr = sqlite3VdbeCurrentAddr(v);
+      codeCompare(pParse, pLeft, pRight, OP_Ge, addr+3, !jumpIfNull);
+
+      sqlite3VdbeAddOp(v, OP_Pop, 1, 0);
+      sqlite3VdbeAddOp(v, OP_Goto, 0, dest);
+      pRight = pExpr->pList->a[1].pExpr;
+      sqlite3ExprCode(pParse, pRight);
+      codeCompare(pParse, pLeft, pRight, OP_Gt, dest, jumpIfNull);
+      break;
+    }
+    default: {
+      sqlite3ExprCode(pParse, pExpr);
+      sqlite3VdbeAddOp(v, OP_IfNot, jumpIfNull, dest);
+      break;
+    }
+  }
+}
+
+/*
+** Do a deep comparison of two expression trees.  Return TRUE (non-zero)
+** if they are identical and return FALSE if they differ in any way.
+*/
+int sqlite3ExprCompare(Expr *pA, Expr *pB){
+  int i;
+  if( pA==0 ){
+    return pB==0;
+  }else if( pB==0 ){
+    return 0;
+  }
+  if( pA->op!=pB->op ) return 0;
+  if( !sqlite3ExprCompare(pA->pLeft, pB->pLeft) ) return 0;
+  if( !sqlite3ExprCompare(pA->pRight, pB->pRight) ) return 0;
+  if( pA->pList ){
+    if( pB->pList==0 ) return 0;
+    if( pA->pList->nExpr!=pB->pList->nExpr ) return 0;
+    for(i=0; i<pA->pList->nExpr; i++){
+      if( !sqlite3ExprCompare(pA->pList->a[i].pExpr, pB->pList->a[i].pExpr) ){
+        return 0;
+      }
+    }
+  }else if( pB->pList ){
+    return 0;
+  }
+  if( pA->pSelect || pB->pSelect ) return 0;
+  if( pA->iTable!=pB->iTable || pA->iColumn!=pB->iColumn ) return 0;
+  if( pA->token.z ){
+    if( pB->token.z==0 ) return 0;
+    if( pB->token.n!=pA->token.n ) return 0;
+    if( sqlite3StrNICmp(pA->token.z, pB->token.z, pB->token.n)!=0 ) return 0;
+  }
+  return 1;
+}
+
+/*
+** Add a new element to the pParse->aAgg[] array and return its index.
+** The new element is initialized to zero.  The calling function is
+** expected to fill it in.
+*/
+static int appendAggInfo(Parse *pParse){
+  if( (pParse->nAgg & 0x7)==0 ){
+    int amt = pParse->nAgg + 8;
+    AggExpr *aAgg = sqliteRealloc(pParse->aAgg, amt*sizeof(pParse->aAgg[0]));
+    if( aAgg==0 ){
+      return -1;
+    }
+    pParse->aAgg = aAgg;
+  }
+  memset(&pParse->aAgg[pParse->nAgg], 0, sizeof(pParse->aAgg[0]));
+  return pParse->nAgg++;
+}
+
+/*
+** This is an xFunc for walkExprTree() used to implement 
+** sqlite3ExprAnalyzeAggregates().  See sqlite3ExprAnalyzeAggregates
+** for additional information.
+**
+** This routine analyzes the aggregate function at pExpr.
+*/
+static int analyzeAggregate(void *pArg, Expr *pExpr){
+  int i;
+  AggExpr *aAgg;
+  NameContext *pNC = (NameContext *)pArg;
+  Parse *pParse = pNC->pParse;
+  SrcList *pSrcList = pNC->pSrcList;
+
+  switch( pExpr->op ){
+    case TK_COLUMN: {
+      for(i=0; pSrcList && i<pSrcList->nSrc; i++){
+        if( pExpr->iTable==pSrcList->a[i].iCursor ){
+          aAgg = pParse->aAgg;
+          for(i=0; i<pParse->nAgg; i++){
+            if( aAgg[i].isAgg ) continue;
+            if( aAgg[i].pExpr->iTable==pExpr->iTable
+             && aAgg[i].pExpr->iColumn==pExpr->iColumn ){
+              break;
+            }
+          }
+          if( i>=pParse->nAgg ){
+            i = appendAggInfo(pParse);
+            if( i<0 ) return 1;
+            pParse->aAgg[i].isAgg = 0;
+            pParse->aAgg[i].pExpr = pExpr;
+          }
+          pExpr->iAgg = i;
+          pExpr->iAggCtx = pNC->nDepth;
+          return 1;
+        }
+      }
+      return 1;
+    }
+    case TK_AGG_FUNCTION: {
+      if( pNC->nDepth==0 ){
+        aAgg = pParse->aAgg;
+        for(i=0; i<pParse->nAgg; i++){
+          if( !aAgg[i].isAgg ) continue;
+          if( sqlite3ExprCompare(aAgg[i].pExpr, pExpr) ){
+            break;
+          }
+        }
+        if( i>=pParse->nAgg ){
+          u8 enc = pParse->db->enc;
+          i = appendAggInfo(pParse);
+          if( i<0 ) return 1;
+          pParse->aAgg[i].isAgg = 1;
+          pParse->aAgg[i].pExpr = pExpr;
+          pParse->aAgg[i].pFunc = sqlite3FindFunction(pParse->db,
+               pExpr->token.z, pExpr->token.n,
+               pExpr->pList ? pExpr->pList->nExpr : 0, enc, 0);
+        }
+        pExpr->iAgg = i;
+        return 1;
+      }
+    }
+  }
+  if( pExpr->pSelect ){
+    pNC->nDepth++;
+    walkSelectExpr(pExpr->pSelect, analyzeAggregate, pNC);
+    pNC->nDepth--;
+  }
+  return 0;
+}
+
+/*
+** Analyze the given expression looking for aggregate functions and
+** for variables that need to be added to the pParse->aAgg[] array.
+** Make additional entries to the pParse->aAgg[] array as necessary.
+**
+** This routine should only be called after the expression has been
+** analyzed by sqlite3ExprResolveNames().
+**
+** If errors are seen, leave an error message in zErrMsg and return
+** the number of errors.
+*/
+int sqlite3ExprAnalyzeAggregates(NameContext *pNC, Expr *pExpr){
+  int nErr = pNC->pParse->nErr;
+  walkExprTree(pExpr, analyzeAggregate, pNC);
+  return pNC->pParse->nErr - nErr;
+}