root/ext/sqlite/libsqlite/src/expr.c

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DEFINITIONS

This source file includes following definitions.
  1. sqliteExpr
  2. sqliteExprSpan
  3. sqliteExprFunction
  4. sqliteExprDelete
  5. sqliteExprDup
  6. sqliteTokenCopy
  7. sqliteExprListDup
  8. sqliteSrcListDup
  9. sqliteIdListDup
  10. sqliteSelectDup
  11. sqliteExprListAppend
  12. sqliteExprListDelete
  13. sqliteExprIsConstant
  14. sqliteExprIsInteger
  15. sqliteIsRowid
  16. lookupName
  17. sqliteExprResolveIds
  18. getFunctionName
  19. sqliteExprCheck
  20. sqliteExprType
  21. sqliteExprCode
  22. sqliteExprCodeExprList
  23. sqliteExprIfTrue
  24. sqliteExprIfFalse
  25. sqliteExprCompare
  26. appendAggInfo
  27. sqliteExprAnalyzeAggregates
  28. sqliteFindFunction

/*
** 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 1.5.4.1 2005/09/07 15:11:32 iliaa Exp $
*/
#include "sqliteInt.h"
#include <ctype.h>

/*
** 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 *sqliteExpr(int op, Expr *pLeft, Expr *pRight, Token *pToken){
  Expr *pNew;
  pNew = sqliteMalloc( sizeof(Expr) );
  if( pNew==0 ){
    /* When malloc fails, we leak memory from pLeft and pRight */
    return 0;
  }
  pNew->op = op;
  pNew->pLeft = pLeft;
  pNew->pRight = pRight;
  if( pToken ){
    assert( pToken->dyn==0 );
    pNew->token = *pToken;
    pNew->span = *pToken;
  }else{
    assert( pNew->token.dyn==0 );
    assert( pNew->token.z==0 );
    assert( pNew->token.n==0 );
    if( pLeft && pRight ){
      sqliteExprSpan(pNew, &pLeft->span, &pRight->span);
    }else{
      pNew->span = pNew->token;
    }
  }
  return pNew;
}

/*
** Set the Expr.span field of the given expression to span all
** text between the two given tokens.
*/
void sqliteExprSpan(Expr *pExpr, Token *pLeft, Token *pRight){
  assert( pRight!=0 );
  assert( pLeft!=0 );
  /* Note: pExpr might be NULL due to a prior malloc failure */
  if( pExpr && pRight->z && pLeft->z ){
    if( pLeft->dyn==0 && pRight->dyn==0 ){
      pExpr->span.z = pLeft->z;
      pExpr->span.n = pRight->n + Addr(pRight->z) - Addr(pLeft->z);
    }else{
      pExpr->span.z = 0;
    }
  }
}

/*
** Construct a new expression node for a function with multiple
** arguments.
*/
Expr *sqliteExprFunction(ExprList *pList, Token *pToken){
  Expr *pNew;
  pNew = sqliteMalloc( sizeof(Expr) );
  if( pNew==0 ){
    /* sqliteExprListDelete(pList); // Leak pList 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;
}

/*
** Recursively delete an expression tree.
*/
void sqliteExprDelete(Expr *p){
  if( p==0 ) return;
  if( p->span.dyn ) sqliteFree((char*)p->span.z);
  if( p->token.dyn ) sqliteFree((char*)p->token.z);
  sqliteExprDelete(p->pLeft);
  sqliteExprDelete(p->pRight);
  sqliteExprListDelete(p->pList);
  sqliteSelectDelete(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 sqliteExprListDup(),
** sqliteIdListDup(), and sqliteSrcListDup() can not be further expanded 
** by subsequent calls to sqlite*ListAppend() routines.
**
** Any tables that the SrcList might point to are not duplicated.
*/
Expr *sqliteExprDup(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 = sqliteExprDup(p->pLeft);
  pNew->pRight = sqliteExprDup(p->pRight);
  pNew->pList = sqliteExprListDup(p->pList);
  pNew->pSelect = sqliteSelectDup(p->pSelect);
  return pNew;
}
void sqliteTokenCopy(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 *sqliteExprListDup(ExprList *p){
  ExprList *pNew;
  struct ExprList_item *pItem;
  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;
  }
  for(i=0; i<p->nExpr; i++, pItem++){
    Expr *pNewExpr, *pOldExpr;
    pItem->pExpr = pNewExpr = sqliteExprDup(pOldExpr = p->a[i].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 */
      sqliteTokenCopy(&pNewExpr->span, &pOldExpr->span);
    }
    assert( pNewExpr==0 || pNewExpr->span.z!=0 
            || pOldExpr->span.z==0 || sqlite_malloc_failed );
    pItem->zName = sqliteStrDup(p->a[i].zName);
    pItem->sortOrder = p->a[i].sortOrder;
    pItem->isAgg = p->a[i].isAgg;
    pItem->done = 0;
  }
  return pNew;
}
SrcList *sqliteSrcListDup(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];
    pNewItem->zDatabase = sqliteStrDup(pOldItem->zDatabase);
    pNewItem->zName = sqliteStrDup(pOldItem->zName);
    pNewItem->zAlias = sqliteStrDup(pOldItem->zAlias);
    pNewItem->jointype = pOldItem->jointype;
    pNewItem->iCursor = pOldItem->iCursor;
    pNewItem->pTab = 0;
    pNewItem->pSelect = sqliteSelectDup(pOldItem->pSelect);
    pNewItem->pOn = sqliteExprDup(pOldItem->pOn);
    pNewItem->pUsing = sqliteIdListDup(pOldItem->pUsing);
  }
  return pNew;
}
IdList *sqliteIdListDup(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 ) 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 *sqliteSelectDup(Select *p){
  Select *pNew;
  if( p==0 ) return 0;
  pNew = sqliteMallocRaw( sizeof(*p) );
  if( pNew==0 ) return 0;
  pNew->isDistinct = p->isDistinct;
  pNew->pEList = sqliteExprListDup(p->pEList);
  pNew->pSrc = sqliteSrcListDup(p->pSrc);
  pNew->pWhere = sqliteExprDup(p->pWhere);
  pNew->pGroupBy = sqliteExprListDup(p->pGroupBy);
  pNew->pHaving = sqliteExprDup(p->pHaving);
  pNew->pOrderBy = sqliteExprListDup(p->pOrderBy);
  pNew->op = p->op;
  pNew->pPrior = sqliteSelectDup(p->pPrior);
  pNew->nLimit = p->nLimit;
  pNew->nOffset = p->nOffset;
  pNew->zSelect = 0;
  pNew->iLimit = -1;
  pNew->iOffset = -1;
  return pNew;
}


/*
** Add a new element to the end of an expression list.  If pList is
** initially NULL, then create a new expression list.
*/
ExprList *sqliteExprListAppend(ExprList *pList, Expr *pExpr, Token *pName){
  if( pList==0 ){
    pList = sqliteMalloc( sizeof(ExprList) );
    if( pList==0 ){
      /* sqliteExprDelete(pExpr); // Leak memory if malloc fails */
      return 0;
    }
    assert( pList->nAlloc==0 );
  }
  if( pList->nAlloc<=pList->nExpr ){
    pList->nAlloc = pList->nAlloc*2 + 4;
    pList->a = sqliteRealloc(pList->a, pList->nAlloc*sizeof(pList->a[0]));
    if( pList->a==0 ){
      /* sqliteExprDelete(pExpr); // Leak memory if malloc fails */
      pList->nExpr = pList->nAlloc = 0;
      return pList;
    }
  }
  assert( pList->a!=0 );
  if( pExpr || pName ){
    struct ExprList_item *pItem = &pList->a[pList->nExpr++];
    memset(pItem, 0, sizeof(*pItem));
    pItem->pExpr = pExpr;
    if( pName ){
      sqliteSetNString(&pItem->zName, pName->z, pName->n, 0);
      sqliteDequote(pItem->zName);
    }
  }
  return pList;
}

/*
** Delete an entire expression list.
*/
void sqliteExprListDelete(ExprList *pList){
  int i;
  if( pList==0 ) return;
  assert( pList->a!=0 || (pList->nExpr==0 && pList->nAlloc==0) );
  assert( pList->nExpr<=pList->nAlloc );
  for(i=0; i<pList->nExpr; i++){
    sqliteExprDelete(pList->a[i].pExpr);
    sqliteFree(pList->a[i].zName);
  }
  sqliteFree(pList->a);
  sqliteFree(pList);
}

/*
** 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 sqliteExprIsConstant(Expr *p){
  switch( p->op ){
    case TK_ID:
    case TK_COLUMN:
    case TK_DOT:
    case TK_FUNCTION:
      return 0;
    case TK_NULL:
    case TK_STRING:
    case TK_INTEGER:
    case TK_FLOAT:
    case TK_VARIABLE:
      return 1;
    default: {
      if( p->pLeft && !sqliteExprIsConstant(p->pLeft) ) return 0;
      if( p->pRight && !sqliteExprIsConstant(p->pRight) ) return 0;
      if( p->pList ){
        int i;
        for(i=0; i<p->pList->nExpr; i++){
          if( !sqliteExprIsConstant(p->pList->a[i].pExpr) ) return 0;
        }
      }
      return p->pLeft!=0 || p->pRight!=0 || (p->pList && p->pList->nExpr>0);
    }
  }
  return 0;
}

/*
** If the given expression 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 sqliteExprIsInteger(Expr *p, int *pValue){
  switch( p->op ){
    case TK_INTEGER: {
      if( sqliteFitsIn32Bits(p->token.z) ){
        *pValue = atoi(p->token.z);
        return 1;
      }
      break;
    }
    case TK_STRING: {
      const char *z = p->token.z;
      int n = p->token.n;
      if( n>0 && z[0]=='-' ){ z++; n--; }
      while( n>0 && *z && isdigit(*z) ){ z++; n--; }
      if( n==0 && sqliteFitsIn32Bits(p->token.z) ){
        *pValue = atoi(p->token.z);
        return 1;
      }
      break;
    }
    case TK_UPLUS: {
      return sqliteExprIsInteger(p->pLeft, pValue);
    }
    case TK_UMINUS: {
      int v;
      if( sqliteExprIsInteger(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 sqliteIsRowid(const char *z){
  if( sqliteStrICmp(z, "_ROWID_")==0 ) return 1;
  if( sqliteStrICmp(z, "ROWID")==0 ) return 1;
  if( sqliteStrICmp(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->dataType      Set to the appropriate data type for the column.
**    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. */
  SrcList *pSrcList,   /* List of tables used to resolve column names */
  ExprList *pEList,    /* List of expressions used to resolve "AS" */
  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 */
  sqlite *db = pParse->db;  /* The database */

  assert( pColumnToken && pColumnToken->z ); /* The Z in X.Y.Z cannot be NULL */
  if( pDbToken && pDbToken->z ){
    zDb = sqliteStrNDup(pDbToken->z, pDbToken->n);
    sqliteDequote(zDb);
  }else{
    zDb = 0;
  }
  if( pTableToken && pTableToken->z ){
    zTab = sqliteStrNDup(pTableToken->z, pTableToken->n);
    sqliteDequote(zTab);
  }else{
    assert( zDb==0 );
    zTab = 0;
  }
  zCol = sqliteStrNDup(pColumnToken->z, pColumnToken->n);
  sqliteDequote(zCol);
  if( sqlite_malloc_failed ){
    return 1;  /* Leak memory (zDb and zTab) if malloc fails */
  }
  assert( zTab==0 || pEList==0 );

  pExpr->iTable = -1;
  for(i=0; i<pSrcList->nSrc; i++){
    struct SrcList_item *pItem = &pSrcList->a[i];
    Table *pTab = pItem->pTab;
    Column *pCol;

    if( pTab==0 ) continue;
    assert( pTab->nCol>0 );
    if( zTab ){
      if( pItem->zAlias ){
        char *zTabName = pItem->zAlias;
        if( sqliteStrICmp(zTabName, zTab)!=0 ) continue;
      }else{
        char *zTabName = pTab->zName;
        if( zTabName==0 || sqliteStrICmp(zTabName, zTab)!=0 ) continue;
        if( zDb!=0 && sqliteStrICmp(db->aDb[pTab->iDb].zName, zDb)!=0 ){
          continue;
        }
      }
    }
    if( 0==(cntTab++) ){
      pExpr->iTable = pItem->iCursor;
      pExpr->iDb = pTab->iDb;
    }
    for(j=0, pCol=pTab->aCol; j<pTab->nCol; j++, pCol++){
      if( sqliteStrICmp(pCol->zName, zCol)==0 ){
        cnt++;
        pExpr->iTable = pItem->iCursor;
        pExpr->iDb = pTab->iDb;
        /* Substitute the rowid (column -1) for the INTEGER PRIMARY KEY */
        pExpr->iColumn = j==pTab->iPKey ? -1 : j;
        pExpr->dataType = pCol->sortOrder & SQLITE_SO_TYPEMASK;
        break;
      }
    }
  }

  /* 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 && sqliteStrICmp("new", zTab) == 0 ){
      pExpr->iTable = pTriggerStack->newIdx;
      assert( pTriggerStack->pTab );
      pTab = pTriggerStack->pTab;
    }else if( pTriggerStack->oldIdx != -1 && sqliteStrICmp("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( sqliteStrICmp(pCol->zName, zCol)==0 ){
          cnt++;
          pExpr->iColumn = j==pTab->iPKey ? -1 : j;
          pExpr->dataType = pCol->sortOrder & SQLITE_SO_TYPEMASK;
          break;
        }
      }
    }
  }

  /*
  ** Perhaps the name is a reference to the ROWID
  */
  if( cnt==0 && cntTab==1 && sqliteIsRowid(zCol) ){
    cnt = 1;
    pExpr->iColumn = -1;
    pExpr->dataType = SQLITE_SO_NUM;
  }

  /*
  ** 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 ){
    for(j=0; j<pEList->nExpr; j++){
      char *zAs = pEList->a[j].zName;
      if( zAs!=0 && sqliteStrICmp(zAs, zCol)==0 ){
        assert( pExpr->pLeft==0 && pExpr->pRight==0 );
        pExpr->op = TK_AS;
        pExpr->iColumn = j;
        pExpr->pLeft = sqliteExprDup(pEList->a[j].pExpr);
        sqliteFree(zCol);
        assert( zTab==0 && zDb==0 );
        return 0;
      }
    } 
  }

  /*
  ** 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.
  */
  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 ){
      sqliteSetString(&z, zDb, ".", zTab, ".", zCol, 0);
    }else if( zTab ){
      sqliteSetString(&z, zTab, ".", zCol, 0);
    }else{
      z = sqliteStrDup(zCol);
    }
    sqliteErrorMsg(pParse, zErr, z);
    sqliteFree(z);
  }

  /* Clean up and return
  */
  sqliteFree(zDb);
  sqliteFree(zTab);
  sqliteFree(zCol);
  sqliteExprDelete(pExpr->pLeft);
  pExpr->pLeft = 0;
  sqliteExprDelete(pExpr->pRight);
  pExpr->pRight = 0;
  pExpr->op = TK_COLUMN;
  sqliteAuthRead(pParse, pExpr, pSrcList);
  return cnt!=1;
}

/*
** 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.
**
** We also check for instances of the IN operator.  IN 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.
**
** This routine also looks for scalar SELECTs that are part of an expression.
** If it finds any, it generates code to write the value of that select
** into a memory cell.
**
** Unknown columns or tables provoke an error.  The function returns
** the number of errors seen and leaves an error message on pParse->zErrMsg.
*/
int sqliteExprResolveIds(
  Parse *pParse,     /* The parser context */
  SrcList *pSrcList, /* List of tables used to resolve column names */
  ExprList *pEList,  /* List of expressions used to resolve "AS" */
  Expr *pExpr        /* The expression to be analyzed. */
){
  int i;

  if( pExpr==0 || pSrcList==0 ) return 0;
  for(i=0; i<pSrcList->nSrc; i++){
    assert( pSrcList->a[i].iCursor>=0 && pSrcList->a[i].iCursor<pParse->nTab );
  }
  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 columnd.
    */
    case TK_ID: {
      if( lookupName(pParse, 0, 0, &pExpr->token, pSrcList, pEList, pExpr) ){
        return 1;
      }
      break; 
    }
  
    /* 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;

      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;
      }
      if( lookupName(pParse, pDb, pTable, pColumn, pSrcList, 0, pExpr) ){
        return 1;
      }
      break;
    }

    case TK_IN: {
      Vdbe *v = sqliteGetVdbe(pParse);
      if( v==0 ) return 1;
      if( sqliteExprResolveIds(pParse, pSrcList, pEList, pExpr->pLeft) ){
        return 1;
      }
      if( pExpr->pSelect ){
        /* Case 1:     expr IN (SELECT ...)
        **
        ** Generate code to write the results of the select into a temporary
        ** table.  The cursor number of the temporary table has already
        ** been put in iTable by sqliteExprResolveInSelect().
        */
        pExpr->iTable = pParse->nTab++;
        sqliteVdbeAddOp(v, OP_OpenTemp, pExpr->iTable, 1);
        sqliteSelect(pParse, pExpr->pSelect, SRT_Set, pExpr->iTable, 0,0,0);
      }else if( pExpr->pList ){
        /* Case 2:     expr IN (exprlist)
        **
        ** Create a set to put the exprlist values in.  The Set id is stored
        ** in iTable.
        */
        int i, iSet;
        for(i=0; i<pExpr->pList->nExpr; i++){
          Expr *pE2 = pExpr->pList->a[i].pExpr;
          if( !sqliteExprIsConstant(pE2) ){
            sqliteErrorMsg(pParse,
              "right-hand side of IN operator must be constant");
            return 1;
          }
          if( sqliteExprCheck(pParse, pE2, 0, 0) ){
            return 1;
          }
        }
        iSet = pExpr->iTable = pParse->nSet++;
        for(i=0; i<pExpr->pList->nExpr; i++){
          Expr *pE2 = pExpr->pList->a[i].pExpr;
          switch( pE2->op ){
            case TK_FLOAT:
            case TK_INTEGER:
            case TK_STRING: {
              int addr;
              assert( pE2->token.z );
              addr = sqliteVdbeOp3(v, OP_SetInsert, iSet, 0,
                                  pE2->token.z, pE2->token.n);
              sqliteVdbeDequoteP3(v, addr);
              break;
            }
            default: {
              sqliteExprCode(pParse, pE2);
              sqliteVdbeAddOp(v, OP_SetInsert, iSet, 0);
              break;
            }
          }
        }
      }
      break;
    }

    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.
      */
      pExpr->iColumn = pParse->nMem++;
      if( sqliteSelect(pParse, pExpr->pSelect, SRT_Mem, pExpr->iColumn,0,0,0) ){
        return 1;
      }
      break;
    }

    /* For all else, just recursively walk the tree */
    default: {
      if( pExpr->pLeft
      && sqliteExprResolveIds(pParse, pSrcList, pEList, pExpr->pLeft) ){
        return 1;
      }
      if( pExpr->pRight 
      && sqliteExprResolveIds(pParse, pSrcList, pEList, pExpr->pRight) ){
        return 1;
      }
      if( pExpr->pList ){
        int i;
        ExprList *pList = pExpr->pList;
        for(i=0; i<pList->nExpr; i++){
          Expr *pArg = pList->a[i].pExpr;
          if( sqliteExprResolveIds(pParse, pSrcList, pEList, pArg) ){
            return 1;
          }
        }
      }
    }
  }
  return 0;
}

/*
** pExpr is a node that defines a function of some kind.  It might
** be a syntactic function like "count(x)" or it might be a function
** that implements an operator, like "a LIKE b".  
**
** This routine makes *pzName point to the name of the function and 
** *pnName hold the number of characters in the function name.
*/
static void getFunctionName(Expr *pExpr, const char **pzName, int *pnName){
  switch( pExpr->op ){
    case TK_FUNCTION: {
      *pzName = pExpr->token.z;
      *pnName = pExpr->token.n;
      break;
    }
    case TK_LIKE: {
      *pzName = "like";
      *pnName = 4;
      break;
    }
    case TK_GLOB: {
      *pzName = "glob";
      *pnName = 4;
      break;
    }
    default: {
      *pzName = "can't happen";
      *pnName = 12;
      break;
    }
  }
}

/*
** Error check the functions in an expression.  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 pIsAgg is not null and this expression is an aggregate function
** (like count(*) or max(value)) then write a 1 into *pIsAgg.
*/
int sqliteExprCheck(Parse *pParse, Expr *pExpr, int allowAgg, int *pIsAgg){
  int nErr = 0;
  if( pExpr==0 ) return 0;
  switch( pExpr->op ){
    case TK_GLOB:
    case TK_LIKE:
    case TK_FUNCTION: {
      int n = pExpr->pList ? pExpr->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;

      getFunctionName(pExpr, &zId, &nId);
      pDef = sqliteFindFunction(pParse->db, zId, nId, n, 0);
      if( pDef==0 ){
        pDef = sqliteFindFunction(pParse->db, zId, nId, -1, 0);
        if( pDef==0 ){
          no_such_func = 1;
        }else{
          wrong_num_args = 1;
        }
      }else{
        is_agg = pDef->xFunc==0;
      }
      if( is_agg && !allowAgg ){
        sqliteErrorMsg(pParse, "misuse of aggregate function %.*s()", nId, zId);
        nErr++;
        is_agg = 0;
      }else if( no_such_func ){
        sqliteErrorMsg(pParse, "no such function: %.*s", nId, zId);
        nErr++;
      }else if( wrong_num_args ){
        sqliteErrorMsg(pParse,"wrong number of arguments to function %.*s()",
             nId, zId);
        nErr++;
      }
      if( is_agg ){
        pExpr->op = TK_AGG_FUNCTION;
        if( pIsAgg ) *pIsAgg = 1;
      }
      for(i=0; nErr==0 && i<n; i++){
        nErr = sqliteExprCheck(pParse, pExpr->pList->a[i].pExpr,
                               allowAgg && !is_agg, pIsAgg);
      }
      if( pDef==0 ){
        /* Already reported an error */
      }else if( pDef->dataType>=0 ){
        if( pDef->dataType<n ){
          pExpr->dataType = 
             sqliteExprType(pExpr->pList->a[pDef->dataType].pExpr);
        }else{
          pExpr->dataType = SQLITE_SO_NUM;
        }
      }else if( pDef->dataType==SQLITE_ARGS ){
        pDef->dataType = SQLITE_SO_TEXT;
        for(i=0; i<n; i++){
          if( sqliteExprType(pExpr->pList->a[i].pExpr)==SQLITE_SO_NUM ){
            pExpr->dataType = SQLITE_SO_NUM;
            break;
          }
        }
      }else if( pDef->dataType==SQLITE_NUMERIC ){
        pExpr->dataType = SQLITE_SO_NUM;
      }else{
        pExpr->dataType = SQLITE_SO_TEXT;
      }
    }
    default: {
      if( pExpr->pLeft ){
        nErr = sqliteExprCheck(pParse, pExpr->pLeft, allowAgg, pIsAgg);
      }
      if( nErr==0 && pExpr->pRight ){
        nErr = sqliteExprCheck(pParse, pExpr->pRight, allowAgg, pIsAgg);
      }
      if( nErr==0 && pExpr->pList ){
        int n = pExpr->pList->nExpr;
        int i;
        for(i=0; nErr==0 && i<n; i++){
          Expr *pE2 = pExpr->pList->a[i].pExpr;
          nErr = sqliteExprCheck(pParse, pE2, allowAgg, pIsAgg);
        }
      }
      break;
    }
  }
  return nErr;
}

/*
** Return either SQLITE_SO_NUM or SQLITE_SO_TEXT to indicate whether the
** given expression should sort as numeric values or as text.
**
** The sqliteExprResolveIds() and sqliteExprCheck() routines must have
** both been called on the expression before it is passed to this routine.
*/
int sqliteExprType(Expr *p){
  if( p==0 ) return SQLITE_SO_NUM;
  while( p ) switch( p->op ){
    case TK_PLUS:
    case TK_MINUS:
    case TK_STAR:
    case TK_SLASH:
    case TK_AND:
    case TK_OR:
    case TK_ISNULL:
    case TK_NOTNULL:
    case TK_NOT:
    case TK_UMINUS:
    case TK_UPLUS:
    case TK_BITAND:
    case TK_BITOR:
    case TK_BITNOT:
    case TK_LSHIFT:
    case TK_RSHIFT:
    case TK_REM:
    case TK_INTEGER:
    case TK_FLOAT:
    case TK_IN:
    case TK_BETWEEN:
    case TK_GLOB:
    case TK_LIKE:
      return SQLITE_SO_NUM;

    case TK_STRING:
    case TK_NULL:
    case TK_CONCAT:
    case TK_VARIABLE:
      return SQLITE_SO_TEXT;

    case TK_LT:
    case TK_LE:
    case TK_GT:
    case TK_GE:
    case TK_NE:
    case TK_EQ:
      if( sqliteExprType(p->pLeft)==SQLITE_SO_NUM ){
        return SQLITE_SO_NUM;
      }
      p = p->pRight;
      break;

    case TK_AS:
      p = p->pLeft;
      break;

    case TK_COLUMN:
    case TK_FUNCTION:
    case TK_AGG_FUNCTION:
      return p->dataType;

    case TK_SELECT:
      assert( p->pSelect );
      assert( p->pSelect->pEList );
      assert( p->pSelect->pEList->nExpr>0 );
      p = p->pSelect->pEList->a[0].pExpr;
      break;

    case TK_CASE: {
      if( p->pRight && sqliteExprType(p->pRight)==SQLITE_SO_NUM ){
        return SQLITE_SO_NUM;
      }
      if( p->pList ){
        int i;
        ExprList *pList = p->pList;
        for(i=1; i<pList->nExpr; i+=2){
          if( sqliteExprType(pList->a[i].pExpr)==SQLITE_SO_NUM ){
            return SQLITE_SO_NUM;
          }
        }
      }
      return SQLITE_SO_TEXT;
    }

    default:
      assert( p->op==TK_ABORT );  /* Can't Happen */
      break;
  }
  return SQLITE_SO_NUM;
}

/*
** Generate code into the current Vdbe to evaluate the given
** expression and leave the result on the top of stack.
*/
void sqliteExprCode(Parse *pParse, Expr *pExpr){
  Vdbe *v = pParse->pVdbe;
  int op;
  if( v==0 || pExpr==0 ) return;
  switch( pExpr->op ){
    case TK_PLUS:     op = OP_Add;      break;
    case TK_MINUS:    op = OP_Subtract; break;
    case TK_STAR:     op = OP_Multiply; break;
    case TK_SLASH:    op = OP_Divide;   break;
    case TK_AND:      op = OP_And;      break;
    case TK_OR:       op = OP_Or;       break;
    case TK_LT:       op = OP_Lt;       break;
    case TK_LE:       op = OP_Le;       break;
    case TK_GT:       op = OP_Gt;       break;
    case TK_GE:       op = OP_Ge;       break;
    case TK_NE:       op = OP_Ne;       break;
    case TK_EQ:       op = OP_Eq;       break;
    case TK_ISNULL:   op = OP_IsNull;   break;
    case TK_NOTNULL:  op = OP_NotNull;  break;
    case TK_NOT:      op = OP_Not;      break;
    case TK_UMINUS:   op = OP_Negative; break;
    case TK_BITAND:   op = OP_BitAnd;   break;
    case TK_BITOR:    op = OP_BitOr;    break;
    case TK_BITNOT:   op = OP_BitNot;   break;
    case TK_LSHIFT:   op = OP_ShiftLeft;  break;
    case TK_RSHIFT:   op = OP_ShiftRight; break;
    case TK_REM:      op = OP_Remainder;  break;
    default: break;
  }
  switch( pExpr->op ){
    case TK_COLUMN: {
      if( pParse->useAgg ){
        sqliteVdbeAddOp(v, OP_AggGet, 0, pExpr->iAgg);
      }else if( pExpr->iColumn>=0 ){
        sqliteVdbeAddOp(v, OP_Column, pExpr->iTable, pExpr->iColumn);
      }else{
        sqliteVdbeAddOp(v, OP_Recno, pExpr->iTable, 0);
      }
      break;
    }
    case TK_STRING:
    case TK_FLOAT:
    case TK_INTEGER: {
      if( pExpr->op==TK_INTEGER && sqliteFitsIn32Bits(pExpr->token.z) ){
        sqliteVdbeAddOp(v, OP_Integer, atoi(pExpr->token.z), 0);
      }else{
        sqliteVdbeAddOp(v, OP_String, 0, 0);
      }
      assert( pExpr->token.z );
      sqliteVdbeChangeP3(v, -1, pExpr->token.z, pExpr->token.n);
      sqliteVdbeDequoteP3(v, -1);
      break;
    }
    case TK_NULL: {
      sqliteVdbeAddOp(v, OP_String, 0, 0);
      break;
    }
    case TK_VARIABLE: {
      sqliteVdbeAddOp(v, OP_Variable, pExpr->iTable, 0);
      break;
    }
    case TK_LT:
    case TK_LE:
    case TK_GT:
    case TK_GE:
    case TK_NE:
    case TK_EQ: {
      if( pParse->db->file_format>=4 && sqliteExprType(pExpr)==SQLITE_SO_TEXT ){
        op += 6;  /* Convert numeric opcodes to text opcodes */
      }
      /* Fall through into the next case */
    }
    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: {
      sqliteExprCode(pParse, pExpr->pLeft);
      sqliteExprCode(pParse, pExpr->pRight);
      sqliteVdbeAddOp(v, op, 0, 0);
      break;
    }
    case TK_LSHIFT:
    case TK_RSHIFT: {
      sqliteExprCode(pParse, pExpr->pRight);
      sqliteExprCode(pParse, pExpr->pLeft);
      sqliteVdbeAddOp(v, op, 0, 0);
      break;
    }
    case TK_CONCAT: {
      sqliteExprCode(pParse, pExpr->pLeft);
      sqliteExprCode(pParse, pExpr->pRight);
      sqliteVdbeAddOp(v, OP_Concat, 2, 0);
      break;
    }
    case TK_UMINUS: {
      assert( pExpr->pLeft );
      if( pExpr->pLeft->op==TK_FLOAT || pExpr->pLeft->op==TK_INTEGER ){
        Token *p = &pExpr->pLeft->token;
        char *z = sqliteMalloc( p->n + 2 );
        sprintf(z, "-%.*s", p->n, p->z);
        if( pExpr->pLeft->op==TK_INTEGER && sqliteFitsIn32Bits(z) ){
          sqliteVdbeAddOp(v, OP_Integer, atoi(z), 0);
        }else{
          sqliteVdbeAddOp(v, OP_String, 0, 0);
        }
        sqliteVdbeChangeP3(v, -1, z, p->n+1);
        sqliteFree(z);
        break;
      }
      /* Fall through into TK_NOT */
    }
    case TK_BITNOT:
    case TK_NOT: {
      sqliteExprCode(pParse, pExpr->pLeft);
      sqliteVdbeAddOp(v, op, 0, 0);
      break;
    }
    case TK_ISNULL:
    case TK_NOTNULL: {
      int dest;
      sqliteVdbeAddOp(v, OP_Integer, 1, 0);
      sqliteExprCode(pParse, pExpr->pLeft);
      dest = sqliteVdbeCurrentAddr(v) + 2;
      sqliteVdbeAddOp(v, op, 1, dest);
      sqliteVdbeAddOp(v, OP_AddImm, -1, 0);
      break;
    }
    case TK_AGG_FUNCTION: {
      sqliteVdbeAddOp(v, OP_AggGet, 0, pExpr->iAgg);
      break;
    }
    case TK_GLOB:
    case TK_LIKE:
    case TK_FUNCTION: {
      ExprList *pList = pExpr->pList;
      int nExpr = pList ? pList->nExpr : 0;
      FuncDef *pDef;
      int nId;
      const char *zId;
      getFunctionName(pExpr, &zId, &nId);
      pDef = sqliteFindFunction(pParse->db, zId, nId, nExpr, 0);
      assert( pDef!=0 );
      nExpr = sqliteExprCodeExprList(pParse, pList, pDef->includeTypes);
      sqliteVdbeOp3(v, OP_Function, nExpr, 0, (char*)pDef, P3_POINTER);
      break;
    }
    case TK_SELECT: {
      sqliteVdbeAddOp(v, OP_MemLoad, pExpr->iColumn, 0);
      break;
    }
    case TK_IN: {
      int addr;
      sqliteVdbeAddOp(v, OP_Integer, 1, 0);
      sqliteExprCode(pParse, pExpr->pLeft);
      addr = sqliteVdbeCurrentAddr(v);
      sqliteVdbeAddOp(v, OP_NotNull, -1, addr+4);
      sqliteVdbeAddOp(v, OP_Pop, 2, 0);
      sqliteVdbeAddOp(v, OP_String, 0, 0);
      sqliteVdbeAddOp(v, OP_Goto, 0, addr+6);
      if( pExpr->pSelect ){
        sqliteVdbeAddOp(v, OP_Found, pExpr->iTable, addr+6);
      }else{
        sqliteVdbeAddOp(v, OP_SetFound, pExpr->iTable, addr+6);
      }
      sqliteVdbeAddOp(v, OP_AddImm, -1, 0);
      break;
    }
    case TK_BETWEEN: {
      sqliteExprCode(pParse, pExpr->pLeft);
      sqliteVdbeAddOp(v, OP_Dup, 0, 0);
      sqliteExprCode(pParse, pExpr->pList->a[0].pExpr);
      sqliteVdbeAddOp(v, OP_Ge, 0, 0);
      sqliteVdbeAddOp(v, OP_Pull, 1, 0);
      sqliteExprCode(pParse, pExpr->pList->a[1].pExpr);
      sqliteVdbeAddOp(v, OP_Le, 0, 0);
      sqliteVdbeAddOp(v, OP_And, 0, 0);
      break;
    }
    case TK_UPLUS:
    case TK_AS: {
      sqliteExprCode(pParse, pExpr->pLeft);
      break;
    }
    case TK_CASE: {
      int expr_end_label;
      int jumpInst;
      int addr;
      int nExpr;
      int i;

      assert(pExpr->pList);
      assert((pExpr->pList->nExpr % 2) == 0);
      assert(pExpr->pList->nExpr > 0);
      nExpr = pExpr->pList->nExpr;
      expr_end_label = sqliteVdbeMakeLabel(v);
      if( pExpr->pLeft ){
        sqliteExprCode(pParse, pExpr->pLeft);
      }
      for(i=0; i<nExpr; i=i+2){
        sqliteExprCode(pParse, pExpr->pList->a[i].pExpr);
        if( pExpr->pLeft ){
          sqliteVdbeAddOp(v, OP_Dup, 1, 1);
          jumpInst = sqliteVdbeAddOp(v, OP_Ne, 1, 0);
          sqliteVdbeAddOp(v, OP_Pop, 1, 0);
        }else{
          jumpInst = sqliteVdbeAddOp(v, OP_IfNot, 1, 0);
        }
        sqliteExprCode(pParse, pExpr->pList->a[i+1].pExpr);
        sqliteVdbeAddOp(v, OP_Goto, 0, expr_end_label);
        addr = sqliteVdbeCurrentAddr(v);
        sqliteVdbeChangeP2(v, jumpInst, addr);
      }
      if( pExpr->pLeft ){
        sqliteVdbeAddOp(v, OP_Pop, 1, 0);
      }
      if( pExpr->pRight ){
        sqliteExprCode(pParse, pExpr->pRight);
      }else{
        sqliteVdbeAddOp(v, OP_String, 0, 0);
      }
      sqliteVdbeResolveLabel(v, expr_end_label);
      break;
    }
    case TK_RAISE: {
      if( !pParse->trigStack ){
        sqliteErrorMsg(pParse,
                       "RAISE() may only be used within a trigger-program");
        pParse->nErr++;
        return;
      }
      if( pExpr->iColumn == OE_Rollback ||
          pExpr->iColumn == OE_Abort ||
          pExpr->iColumn == OE_Fail ){
          sqliteVdbeOp3(v, OP_Halt, SQLITE_CONSTRAINT, pExpr->iColumn,
                           pExpr->token.z, pExpr->token.n);
          sqliteVdbeDequoteP3(v, -1);
      } else {
          assert( pExpr->iColumn == OE_Ignore );
          sqliteVdbeOp3(v, OP_Goto, 0, pParse->trigStack->ignoreJump,
                           "(IGNORE jump)", 0);
      }
    }
    break;
  }
}

/*
** Generate code that pushes the value of every element of the given
** expression list onto the stack.  If the includeTypes flag is true,
** then also push a string that is the datatype of each element onto
** the stack after the value.
**
** Return the number of elements pushed onto the stack.
*/
int sqliteExprCodeExprList(
  Parse *pParse,     /* Parsing context */
  ExprList *pList,   /* The expression list to be coded */
  int includeTypes   /* TRUE to put datatypes on the stack too */
){
  struct ExprList_item *pItem;
  int i, n;
  Vdbe *v;
  if( pList==0 ) return 0;
  v = sqliteGetVdbe(pParse);
  n = pList->nExpr;
  for(pItem=pList->a, i=0; i<n; i++, pItem++){
    sqliteExprCode(pParse, pItem->pExpr);
    if( includeTypes ){
      sqliteVdbeOp3(v, OP_String, 0, 0, 
         sqliteExprType(pItem->pExpr)==SQLITE_SO_NUM ? "numeric" : "text",
         P3_STATIC);
    }
  }
  return includeTypes ? n*2 : 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.
*/
void sqliteExprIfTrue(Parse *pParse, Expr *pExpr, int dest, int jumpIfNull){
  Vdbe *v = pParse->pVdbe;
  int op = 0;
  if( v==0 || pExpr==0 ) return;
  switch( pExpr->op ){
    case TK_LT:       op = OP_Lt;       break;
    case TK_LE:       op = OP_Le;       break;
    case TK_GT:       op = OP_Gt;       break;
    case TK_GE:       op = OP_Ge;       break;
    case TK_NE:       op = OP_Ne;       break;
    case TK_EQ:       op = OP_Eq;       break;
    case TK_ISNULL:   op = OP_IsNull;   break;
    case TK_NOTNULL:  op = OP_NotNull;  break;
    default:  break;
  }
  switch( pExpr->op ){
    case TK_AND: {
      int d2 = sqliteVdbeMakeLabel(v);
      sqliteExprIfFalse(pParse, pExpr->pLeft, d2, !jumpIfNull);
      sqliteExprIfTrue(pParse, pExpr->pRight, dest, jumpIfNull);
      sqliteVdbeResolveLabel(v, d2);
      break;
    }
    case TK_OR: {
      sqliteExprIfTrue(pParse, pExpr->pLeft, dest, jumpIfNull);
      sqliteExprIfTrue(pParse, pExpr->pRight, dest, jumpIfNull);
      break;
    }
    case TK_NOT: {
      sqliteExprIfFalse(pParse, pExpr->pLeft, dest, jumpIfNull);
      break;
    }
    case TK_LT:
    case TK_LE:
    case TK_GT:
    case TK_GE:
    case TK_NE:
    case TK_EQ: {
      sqliteExprCode(pParse, pExpr->pLeft);
      sqliteExprCode(pParse, pExpr->pRight);
      if( pParse->db->file_format>=4 && sqliteExprType(pExpr)==SQLITE_SO_TEXT ){
        op += 6;  /* Convert numeric opcodes to text opcodes */
      }
      sqliteVdbeAddOp(v, op, jumpIfNull, dest);
      break;
    }
    case TK_ISNULL:
    case TK_NOTNULL: {
      sqliteExprCode(pParse, pExpr->pLeft);
      sqliteVdbeAddOp(v, op, 1, dest);
      break;
    }
    case TK_IN: {
      int addr;
      sqliteExprCode(pParse, pExpr->pLeft);
      addr = sqliteVdbeCurrentAddr(v);
      sqliteVdbeAddOp(v, OP_NotNull, -1, addr+3);
      sqliteVdbeAddOp(v, OP_Pop, 1, 0);
      sqliteVdbeAddOp(v, OP_Goto, 0, jumpIfNull ? dest : addr+4);
      if( pExpr->pSelect ){
        sqliteVdbeAddOp(v, OP_Found, pExpr->iTable, dest);
      }else{
        sqliteVdbeAddOp(v, OP_SetFound, pExpr->iTable, dest);
      }
      break;
    }
    case TK_BETWEEN: {
      int addr;
      sqliteExprCode(pParse, pExpr->pLeft);
      sqliteVdbeAddOp(v, OP_Dup, 0, 0);
      sqliteExprCode(pParse, pExpr->pList->a[0].pExpr);
      addr = sqliteVdbeAddOp(v, OP_Lt, !jumpIfNull, 0);
      sqliteExprCode(pParse, pExpr->pList->a[1].pExpr);
      sqliteVdbeAddOp(v, OP_Le, jumpIfNull, dest);
      sqliteVdbeAddOp(v, OP_Integer, 0, 0);
      sqliteVdbeChangeP2(v, addr, sqliteVdbeCurrentAddr(v));
      sqliteVdbeAddOp(v, OP_Pop, 1, 0);
      break;
    }
    default: {
      sqliteExprCode(pParse, pExpr);
      sqliteVdbeAddOp(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 sqliteExprIfFalse(Parse *pParse, Expr *pExpr, int dest, int jumpIfNull){
  Vdbe *v = pParse->pVdbe;
  int op = 0;
  if( v==0 || pExpr==0 ) return;
  switch( pExpr->op ){
    case TK_LT:       op = OP_Ge;       break;
    case TK_LE:       op = OP_Gt;       break;
    case TK_GT:       op = OP_Le;       break;
    case TK_GE:       op = OP_Lt;       break;
    case TK_NE:       op = OP_Eq;       break;
    case TK_EQ:       op = OP_Ne;       break;
    case TK_ISNULL:   op = OP_NotNull;  break;
    case TK_NOTNULL:  op = OP_IsNull;   break;
    default:  break;
  }
  switch( pExpr->op ){
    case TK_AND: {
      sqliteExprIfFalse(pParse, pExpr->pLeft, dest, jumpIfNull);
      sqliteExprIfFalse(pParse, pExpr->pRight, dest, jumpIfNull);
      break;
    }
    case TK_OR: {
      int d2 = sqliteVdbeMakeLabel(v);
      sqliteExprIfTrue(pParse, pExpr->pLeft, d2, !jumpIfNull);
      sqliteExprIfFalse(pParse, pExpr->pRight, dest, jumpIfNull);
      sqliteVdbeResolveLabel(v, d2);
      break;
    }
    case TK_NOT: {
      sqliteExprIfTrue(pParse, pExpr->pLeft, dest, jumpIfNull);
      break;
    }
    case TK_LT:
    case TK_LE:
    case TK_GT:
    case TK_GE:
    case TK_NE:
    case TK_EQ: {
      if( pParse->db->file_format>=4 && sqliteExprType(pExpr)==SQLITE_SO_TEXT ){
        /* Convert numeric comparison opcodes into text comparison opcodes.
        ** This step depends on the fact that the text comparision opcodes are
        ** always 6 greater than their corresponding numeric comparison
        ** opcodes.
        */
        assert( OP_Eq+6 == OP_StrEq );
        op += 6;
      }
      sqliteExprCode(pParse, pExpr->pLeft);
      sqliteExprCode(pParse, pExpr->pRight);
      sqliteVdbeAddOp(v, op, jumpIfNull, dest);
      break;
    }
    case TK_ISNULL:
    case TK_NOTNULL: {
      sqliteExprCode(pParse, pExpr->pLeft);
      sqliteVdbeAddOp(v, op, 1, dest);
      break;
    }
    case TK_IN: {
      int addr;
      sqliteExprCode(pParse, pExpr->pLeft);
      addr = sqliteVdbeCurrentAddr(v);
      sqliteVdbeAddOp(v, OP_NotNull, -1, addr+3);
      sqliteVdbeAddOp(v, OP_Pop, 1, 0);
      sqliteVdbeAddOp(v, OP_Goto, 0, jumpIfNull ? dest : addr+4);
      if( pExpr->pSelect ){
        sqliteVdbeAddOp(v, OP_NotFound, pExpr->iTable, dest);
      }else{
        sqliteVdbeAddOp(v, OP_SetNotFound, pExpr->iTable, dest);
      }
      break;
    }
    case TK_BETWEEN: {
      int addr;
      sqliteExprCode(pParse, pExpr->pLeft);
      sqliteVdbeAddOp(v, OP_Dup, 0, 0);
      sqliteExprCode(pParse, pExpr->pList->a[0].pExpr);
      addr = sqliteVdbeCurrentAddr(v);
      sqliteVdbeAddOp(v, OP_Ge, !jumpIfNull, addr+3);
      sqliteVdbeAddOp(v, OP_Pop, 1, 0);
      sqliteVdbeAddOp(v, OP_Goto, 0, dest);
      sqliteExprCode(pParse, pExpr->pList->a[1].pExpr);
      sqliteVdbeAddOp(v, OP_Gt, jumpIfNull, dest);
      break;
    }
    default: {
      sqliteExprCode(pParse, pExpr);
      sqliteVdbeAddOp(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 sqliteExprCompare(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( !sqliteExprCompare(pA->pLeft, pB->pLeft) ) return 0;
  if( !sqliteExprCompare(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( !sqliteExprCompare(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( sqliteStrNICmp(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.
*/
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++;
}

/*
** 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 sqliteExprResolveIds() and sqliteExprCheck().
**
** If errors are seen, leave an error message in zErrMsg and return
** the number of errors.
*/
int sqliteExprAnalyzeAggregates(Parse *pParse, Expr *pExpr){
  int i;
  AggExpr *aAgg;
  int nErr = 0;

  if( pExpr==0 ) return 0;
  switch( pExpr->op ){
    case TK_COLUMN: {
      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;
      break;
    }
    case TK_AGG_FUNCTION: {
      aAgg = pParse->aAgg;
      for(i=0; i<pParse->nAgg; i++){
        if( !aAgg[i].isAgg ) continue;
        if( sqliteExprCompare(aAgg[i].pExpr, pExpr) ){
          break;
        }
      }
      if( i>=pParse->nAgg ){
        i = appendAggInfo(pParse);
        if( i<0 ) return 1;
        pParse->aAgg[i].isAgg = 1;
        pParse->aAgg[i].pExpr = pExpr;
        pParse->aAgg[i].pFunc = sqliteFindFunction(pParse->db,
             pExpr->token.z, pExpr->token.n,
             pExpr->pList ? pExpr->pList->nExpr : 0, 0);
      }
      pExpr->iAgg = i;
      break;
    }
    default: {
      if( pExpr->pLeft ){
        nErr = sqliteExprAnalyzeAggregates(pParse, pExpr->pLeft);
      }
      if( nErr==0 && pExpr->pRight ){
        nErr = sqliteExprAnalyzeAggregates(pParse, pExpr->pRight);
      }
      if( nErr==0 && pExpr->pList ){
        int n = pExpr->pList->nExpr;
        int i;
        for(i=0; nErr==0 && i<n; i++){
          nErr = sqliteExprAnalyzeAggregates(pParse, pExpr->pList->a[i].pExpr);
        }
      }
      break;
    }
  }
  return nErr;
}

/*
** Locate a user function given a name and a number of arguments.
** Return a pointer to the FuncDef structure that defines that
** function, or return NULL if the function does not exist.
**
** If the createFlag argument is true, then a new (blank) FuncDef
** structure is created and liked into the "db" structure if a
** no matching function previously existed.  When createFlag is true
** and the nArg parameter is -1, then only a function that accepts
** any number of arguments will be returned.
**
** If createFlag is false and nArg is -1, then the first valid
** function found is returned.  A function is valid if either xFunc
** or xStep is non-zero.
*/
FuncDef *sqliteFindFunction(
  sqlite *db,        /* An open database */
  const char *zName, /* Name of the function.  Not null-terminated */
  int nName,         /* Number of characters in the name */
  int nArg,          /* Number of arguments.  -1 means any number */
  int createFlag     /* Create new entry if true and does not otherwise exist */
){
  FuncDef *pFirst, *p, *pMaybe;
  pFirst = p = (FuncDef*)sqliteHashFind(&db->aFunc, zName, nName);
  if( p && !createFlag && nArg<0 ){
    while( p && p->xFunc==0 && p->xStep==0 ){ p = p->pNext; }
    return p;
  }
  pMaybe = 0;
  while( p && p->nArg!=nArg ){
    if( p->nArg<0 && !createFlag && (p->xFunc || p->xStep) ) pMaybe = p;
    p = p->pNext;
  }
  if( p && !createFlag && p->xFunc==0 && p->xStep==0 ){
    return 0;
  }
  if( p==0 && pMaybe ){
    assert( createFlag==0 );
    return pMaybe;
  }
  if( p==0 && createFlag && (p = sqliteMalloc(sizeof(*p)))!=0 ){
    p->nArg = nArg;
    p->pNext = pFirst;
    p->dataType = pFirst ? pFirst->dataType : SQLITE_NUMERIC;
    sqliteHashInsert(&db->aFunc, zName, nName, (void*)p);
  }
  return p;
}

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