** used in a context in which there is no difference between a result
** of 0 and one of NULL. For example:
**
**     ... WHERE (?,?) IN (SELECT ...)
**
*/
#ifndef SQLITE_OMIT_SUBQUERY
static Select *isCandidateForInOpt(Expr *pX, int bNullSensitive){
  Select *p;
  SrcList *pSrc;
  ExprList *pEList;
  Table *pTab;
  int i;
  if( !ExprHasProperty(pX, EP_xIsSelect) ) return 0;  /* Not a subquery */
  if( ExprHasProperty(pX, EP_VarSelect)  ) return 0;  /* Correlated subq */
................................................................................
  if( pSrc->a[0].pSelect ) return 0;     /* FROM is not a subquery or view */
  pTab = pSrc->a[0].pTab;
  assert( pTab!=0 );
  assert( pTab->pSelect==0 );            /* FROM clause is not a view */
  if( IsVirtual(pTab) ) return 0;        /* FROM clause not a virtual table */
  pEList = p->pEList;

  /* All SELECT results must be columns. If the SELECT returns more than
  ** one column and the bNullSensitive flag is set, all returned columns
  ** must be declared NOT NULL. */
  for(i=0; i<pEList->nExpr; i++){
    Expr *pRes = pEList->a[i].pExpr;
    if( pRes->op!=TK_COLUMN ) return 0;
    assert( pRes->iTable==pSrc->a[0].iCursor );  /* Not a correlated subquery */
    if( pEList->nExpr>1 && bNullSensitive ){
      if( pTab->aCol[pRes->iColumn].notNull==0 ) return 0;
    }
  }
  return p;
}
#endif /* SQLITE_OMIT_SUBQUERY */

/*
** Code an OP_Once instruction and allocate space for its flag. Return the 
................................................................................
  int eType = 0;                        /* Type of RHS table. IN_INDEX_* */
  int iTab = pParse->nTab++;            /* Cursor of the RHS table */
  int mustBeUnique;                     /* True if RHS must be unique */
  Vdbe *v = sqlite3GetVdbe(pParse);     /* Virtual machine being coded */

  assert( pX->op==TK_IN );
  mustBeUnique = (inFlags & IN_INDEX_LOOP)!=0;


















  /* Check to see if an existing table or index can be used to
  ** satisfy the query.  This is preferable to generating a new 
  ** ephemeral table.
  */
  if( pParse->nErr==0 && (p = isCandidateForInOpt(pX, prRhsHasNull!=0))!=0 ){
    sqlite3 *db = pParse->db;              /* Database connection */
    Table *pTab;                           /* Table <table>. */
    i16 iDb;                               /* Database idx for pTab */
    ExprList *pEList = p->pEList;
    int nExpr = pEList->nExpr;

    assert( p->pEList!=0 );             /* Because of isCandidateForInOpt(p) */
................................................................................
          int iAddr = sqlite3CodeOnce(pParse); VdbeCoverage(v);
          sqlite3VdbeAddOp3(v, OP_OpenRead, iTab, pIdx->tnum, iDb);
          sqlite3VdbeSetP4KeyInfo(pParse, pIdx);
          VdbeComment((v, "%s", pIdx->zName));
          assert( IN_INDEX_INDEX_DESC == IN_INDEX_INDEX_ASC+1 );
          eType = IN_INDEX_INDEX_ASC + pIdx->aSortOrder[0];

          if( prRhsHasNull && nExpr==1 
           && !pTab->aCol[pEList->a[0].pExpr->iColumn].notNull 
          ){
#ifdef SQLITE_ENABLE_COLUMN_USED_MASK
            i64 mask = (1<<nExpr)-1;
            sqlite3VdbeAddOp4Dup8(v, OP_ColumnsUsed, 
                iTab, 0, 0, (u8*)&mask, P4_INT64);
#endif
            *prRhsHasNull = ++pParse->nMem;
            sqlite3SetHasNullFlag(v, iTab, *prRhsHasNull);

          }
          sqlite3VdbeJumpHere(v, iAddr);
        }
      }
    }
  }

................................................................................
    sqlite3VdbeJumpHere(v, jmpIfDynamic);
  }
  sqlite3ExprCachePop(pParse);

  return rReg;
}
#endif /* SQLITE_OMIT_SUBQUERY */



























#ifndef SQLITE_OMIT_SUBQUERY
/*
** Generate code for an IN expression.
**
**      x IN (SELECT ...)
**      x IN (value, value, ...)
................................................................................
  int *aiMap = 0;       /* Map from vector field to index column */
  char *zAff = 0;       /* Affinity string for comparisons */
  int nVector;          /* Size of vectors for this IN(...) op */
  int regSelect = 0;
  Expr *pLeft = pExpr->pLeft;
  int i;


  nVector = sqlite3ExprVectorSize(pExpr->pLeft);
  aiMap = (int*)sqlite3DbMallocZero(
      pParse->db, nVector*(sizeof(int) + sizeof(char)) + 1
  );
  if( !aiMap ) return;
  zAff = (char*)&aiMap[nVector];


  /* Attempt to compute the RHS. After this step, if anything other than
  ** IN_INDEX_NOOP is returned, the table opened ith cursor pExpr->iTable 
  ** contains the values that make up the RHS. If IN_INDEX_NOOP is returned,
  ** the RHS has not yet been coded.  */
  v = pParse->pVdbe;
  assert( v!=0 );       /* OOM detected prior to this routine */
................................................................................
      sqlite3VdbeAddOp2(v, OP_IsNull, regCkNull, destIfNull); VdbeCoverage(v);
      sqlite3VdbeGoto(v, destIfFalse);
    }
    sqlite3VdbeResolveLabel(v, labelOk);
    sqlite3ReleaseTempReg(pParse, regCkNull);
  }else{
  







    /* If the LHS is NULL, then the result is either false or NULL depending
    ** on whether the RHS is empty or not, respectively.  */

    if( destIfNull==destIfFalse ){
      for(i=0; i<nVector; i++){
        Expr *p = exprVectorField(pExpr->pLeft, i);
        if( sqlite3ExprCanBeNull(p) ){
          sqlite3VdbeAddOp2(v, OP_IsNull, r1+aiMap[i], destIfNull);
        }
      }
................................................................................
      sqlite3VdbeAddOp2(v, OP_Rewind, pExpr->iTable, destIfFalse);
      VdbeCoverage(v);
      sqlite3VdbeGoto(v, destIfNull);
      sqlite3VdbeJumpHere(v, addr1);
    }
  
    if( eType==IN_INDEX_ROWID ){
      /* In this case, the RHS is the ROWID of table b-tree
      */
      sqlite3VdbeAddOp3(v, OP_SeekRowid, pExpr->iTable, destIfFalse, r1);
      VdbeCoverage(v);





    }else if( nVector>1 && eType==IN_INDEX_EPH && destIfNull!=destIfFalse ){
      int regNull = sqlite3GetTempReg(pParse);
      int r2 = sqlite3GetTempReg(pParse);
      int r3 = sqlite3GetTempReg(pParse);
      int r4 = sqlite3GetTempReg(pParse);

      int addrNext;
      int addrIf;

      if( destIfFalse!=destIfNull ){
        sqlite3VdbeAddOp2(v, OP_Integer, 0, regNull);

      }



      addrNext = sqlite3VdbeAddOp2(v, OP_Rewind, pExpr->iTable, destIfFalse);

      for(i=0; i<nVector; i++){
        Expr *p;
        CollSeq *pColl;

        p = exprVectorField(pLeft, i);
        pColl = sqlite3ExprCollSeq(pParse, p);

        sqlite3VdbeAddOp3(v, OP_Column, pExpr->iTable, i, r2);
        sqlite3VdbeAddOp4(v, OP_Eq, r1+i, i?r3:r4, r2, (void*)pColl,P4_COLLSEQ);
        sqlite3VdbeChangeP5(v, SQLITE_STOREP2);
        if( i!=0 ){
          sqlite3VdbeAddOp3(v, OP_And, r3, r4, r4);



        }

      }
      addrIf = sqlite3VdbeAddOp1(v, OP_If, r4);
      if( destIfNull!=destIfFalse ){
        sqlite3VdbeAddOp2(v, OP_IfNot, r4, sqlite3VdbeCurrentAddr(v)+2);







        sqlite3VdbeAddOp2(v, OP_Integer, 1, regNull);
      }
      sqlite3VdbeAddOp2(v, OP_Next, pExpr->iTable, addrNext+1);
      if( destIfNull!=destIfFalse ){
        sqlite3VdbeAddOp2(v, OP_If, regNull, destIfNull);
      }
      sqlite3VdbeAddOp2(v, OP_Goto, 0, destIfFalse);
      sqlite3VdbeChangeP2(v, addrIf, sqlite3VdbeCurrentAddr(v));
      sqlite3ReleaseTempReg(pParse, regNull);
      sqlite3ReleaseTempReg(pParse, r2);
      sqlite3ReleaseTempReg(pParse, r3);
      sqlite3ReleaseTempReg(pParse, r4);
    }else{
      /* In this case, the RHS is an index b-tree.
      */
      sqlite3VdbeAddOp4(v, OP_Affinity, r1, nVector, 0, zAff, nVector);
  
      /* If the set membership test fails, then the result of the 
      ** "x IN (...)" expression must be either 0 or NULL. If the set
      ** contains no NULL values, then the result is 0. If the set 
      ** contains one or more NULL values, then the result of the
      ** expression is also NULL.
      */
      assert( destIfFalse!=destIfNull || rRhsHasNull==0 );
      if( rRhsHasNull==0 ){
        /* This branch runs if it is known at compile time that the RHS
        ** cannot contain NULL values. This happens as the result
        ** of a "NOT NULL" constraint in the database schema.
        **
        ** Also run this branch if NULL is equivalent to FALSE
        ** for this particular IN operator.
        */
        sqlite3VdbeAddOp4Int(
            v, OP_NotFound, pExpr->iTable, destIfFalse, r1, nVector
        );
        VdbeCoverage(v);
      }else{
        /* In this branch, the RHS of the IN might contain a NULL and
        ** the presence of a NULL on the RHS makes a difference in the
        ** outcome.
        */
        int addr1;
  
        /* First check to see if the LHS is contained in the RHS.  If so,
        ** then the answer is TRUE the presence of NULLs in the RHS does
        ** not matter.  If the LHS is not contained in the RHS, then the
        ** answer is NULL if the RHS contains NULLs and the answer is
        ** FALSE if the RHS is NULL-free.
        */
        addr1 = sqlite3VdbeAddOp4Int(v, OP_Found, pExpr->iTable, 0, r1, 1);
................................................................................
*/
int sqlite3ExprCodeTarget(Parse *pParse, Expr *pExpr, int target){
  Vdbe *v = pParse->pVdbe;  /* The VM under construction */
  int op;                   /* The opcode being coded */
  int inReg = target;       /* Results stored in register inReg */
  int regFree1 = 0;         /* If non-zero free this temporary register */
  int regFree2 = 0;         /* If non-zero free this temporary register */
  int r1, r2, r3, r4;       /* Various register numbers */
  sqlite3 *db = pParse->db; /* The database connection */
  Expr tempX;               /* Temporary expression node */
  int p5 = 0;

  assert( target>0 && target<=pParse->nMem );
  if( v==0 ){
    assert( pParse->db->mallocFailed );
................................................................................
    **
    ** X is stored in pExpr->pLeft.
    ** Y is stored in pExpr->pList->a[0].pExpr.
    ** Z is stored in pExpr->pList->a[1].pExpr.
    */
    case TK_BETWEEN: {
      exprCodeBetween(pParse, pExpr, target, 0, 0);
#if 0
      Expr *pLeft = pExpr->pLeft;
      struct ExprList_item *pLItem = pExpr->x.pList->a;
      Expr *pRight = pLItem->pExpr;

      r1 = sqlite3ExprCodeTemp(pParse, pLeft, &regFree1);
      r2 = sqlite3ExprCodeTemp(pParse, pRight, &regFree2);
      testcase( regFree1==0 );
      testcase( regFree2==0 );
      r3 = sqlite3GetTempReg(pParse);
      r4 = sqlite3GetTempReg(pParse);
      codeCompare(pParse, pLeft, pRight, OP_Ge,
                  r1, r2, r3, SQLITE_STOREP2);  VdbeCoverage(v);
      pLItem++;
      pRight = pLItem->pExpr;
      sqlite3ReleaseTempReg(pParse, regFree2);
      r2 = sqlite3ExprCodeTemp(pParse, pRight, &regFree2);
      testcase( regFree2==0 );
      codeCompare(pParse, pLeft, pRight, OP_Le, r1, r2, r4, SQLITE_STOREP2);
      VdbeCoverage(v);
      sqlite3VdbeAddOp3(v, OP_And, r3, r4, target);
      sqlite3ReleaseTempReg(pParse, r3);
      sqlite3ReleaseTempReg(pParse, r4);
#endif
      break;
    }
    case TK_SPAN:
    case TK_COLLATE: 
    case TK_UPLUS: {
      inReg = sqlite3ExprCodeTarget(pParse, pExpr->pLeft, target);
      break;
................................................................................
  int regFree2 = 0;
  int r1, r2;

  assert( jumpIfNull==SQLITE_JUMPIFNULL || jumpIfNull==0 );
  if( NEVER(v==0) )     return;  /* Existence of VDBE checked by caller */
  if( NEVER(pExpr==0) ) return;  /* No way this can happen */
  op = pExpr->op;
  switch( op | (pExpr->pLeft ? (pExpr->pLeft->flags & EP_Vector) : 0)){
    case TK_AND: {
      int d2 = sqlite3VdbeMakeLabel(v);
      testcase( jumpIfNull==0 );
      sqlite3ExprIfFalse(pParse, pExpr->pLeft, d2,jumpIfNull^SQLITE_JUMPIFNULL);
      sqlite3ExprCachePush(pParse);
      sqlite3ExprIfTrue(pParse, pExpr->pRight, dest, jumpIfNull);
      sqlite3VdbeResolveLabel(v, d2);
................................................................................
      /* Fall thru */
    case TK_LT:
    case TK_LE:
    case TK_GT:
    case TK_GE:
    case TK_NE:
    case TK_EQ: {

      testcase( jumpIfNull==0 );
      r1 = sqlite3ExprCodeTemp(pParse, pExpr->pLeft, &regFree1);
      r2 = sqlite3ExprCodeTemp(pParse, pExpr->pRight, &regFree2);
      codeCompare(pParse, pExpr->pLeft, pExpr->pRight, op,
                  r1, r2, dest, jumpIfNull);
      assert(TK_LT==OP_Lt); testcase(op==OP_Lt); VdbeCoverageIf(v,op==OP_Lt);
      assert(TK_LE==OP_Le); testcase(op==OP_Le); VdbeCoverageIf(v,op==OP_Le);
................................................................................
      sqlite3ExprCodeIN(pParse, pExpr, destIfFalse, destIfNull);
      sqlite3VdbeGoto(v, dest);
      sqlite3VdbeResolveLabel(v, destIfFalse);
      break;
    }
#endif
    default: {

      if( exprAlwaysTrue(pExpr) ){
        sqlite3VdbeGoto(v, dest);
      }else if( exprAlwaysFalse(pExpr) ){
        /* No-op */
      }else{
        r1 = sqlite3ExprCodeTemp(pParse, pExpr, &regFree1);
        sqlite3VdbeAddOp3(v, OP_If, r1, dest, jumpIfNull!=0);

** used in a context in which there is no difference between a result
** of 0 and one of NULL. For example:
**
**     ... WHERE (?,?) IN (SELECT ...)
**
*/
#ifndef SQLITE_OMIT_SUBQUERY
static Select *isCandidateForInOpt(Expr *pX){
  Select *p;
  SrcList *pSrc;
  ExprList *pEList;
  Table *pTab;
  int i;
  if( !ExprHasProperty(pX, EP_xIsSelect) ) return 0;  /* Not a subquery */
  if( ExprHasProperty(pX, EP_VarSelect)  ) return 0;  /* Correlated subq */
................................................................................
  if( pSrc->a[0].pSelect ) return 0;     /* FROM is not a subquery or view */
  pTab = pSrc->a[0].pTab;
  assert( pTab!=0 );
  assert( pTab->pSelect==0 );            /* FROM clause is not a view */
  if( IsVirtual(pTab) ) return 0;        /* FROM clause not a virtual table */
  pEList = p->pEList;

  /* All SELECT results must be columns. */


  for(i=0; i<pEList->nExpr; i++){
    Expr *pRes = pEList->a[i].pExpr;
    if( pRes->op!=TK_COLUMN ) return 0;
    assert( pRes->iTable==pSrc->a[0].iCursor );  /* Not a correlated subquery */



  }
  return p;
}
#endif /* SQLITE_OMIT_SUBQUERY */

/*
** Code an OP_Once instruction and allocate space for its flag. Return the 
................................................................................
  int eType = 0;                        /* Type of RHS table. IN_INDEX_* */
  int iTab = pParse->nTab++;            /* Cursor of the RHS table */
  int mustBeUnique;                     /* True if RHS must be unique */
  Vdbe *v = sqlite3GetVdbe(pParse);     /* Virtual machine being coded */

  assert( pX->op==TK_IN );
  mustBeUnique = (inFlags & IN_INDEX_LOOP)!=0;

  /* If the RHS of this IN(...) operator is a SELECT, and if it matters 
  ** whether or not the SELECT result contains NULL values, check whether
  ** or not NULL is actuall possible (it may not be, for example, due 
  ** to NOT NULL constraints in the schema). If no NULL values are possible,
  ** set prRhsHasNull to 0 before continuing.
  */
  if( prRhsHasNull && (pX->flags & EP_xIsSelect) ){
    int i;
    ExprList *pEList = pX->x.pSelect->pEList;
    for(i=0; i<pEList->nExpr; i++){
      if( sqlite3ExprCanBeNull(pEList->a[i].pExpr) ) break;
    }
    if( i==pEList->nExpr ){
      prRhsHasNull = 0;
    }
  }

  /* Check to see if an existing table or index can be used to
  ** satisfy the query.  This is preferable to generating a new 
  ** ephemeral table.  */

  if( pParse->nErr==0 && (p = isCandidateForInOpt(pX))!=0 ){
    sqlite3 *db = pParse->db;              /* Database connection */
    Table *pTab;                           /* Table <table>. */
    i16 iDb;                               /* Database idx for pTab */
    ExprList *pEList = p->pEList;
    int nExpr = pEList->nExpr;

    assert( p->pEList!=0 );             /* Because of isCandidateForInOpt(p) */
................................................................................
          int iAddr = sqlite3CodeOnce(pParse); VdbeCoverage(v);
          sqlite3VdbeAddOp3(v, OP_OpenRead, iTab, pIdx->tnum, iDb);
          sqlite3VdbeSetP4KeyInfo(pParse, pIdx);
          VdbeComment((v, "%s", pIdx->zName));
          assert( IN_INDEX_INDEX_DESC == IN_INDEX_INDEX_ASC+1 );
          eType = IN_INDEX_INDEX_ASC + pIdx->aSortOrder[0];

          if( prRhsHasNull ){
            *prRhsHasNull = ++pParse->nMem;

#ifdef SQLITE_ENABLE_COLUMN_USED_MASK
            i64 mask = (1<<nExpr)-1;
            sqlite3VdbeAddOp4Dup8(v, OP_ColumnsUsed, 
                iTab, 0, 0, (u8*)&mask, P4_INT64);
#endif
            if( nExpr==1 ){
              sqlite3SetHasNullFlag(v, iTab, *prRhsHasNull);
            }
          }
          sqlite3VdbeJumpHere(v, iAddr);
        }
      }
    }
  }

................................................................................
    sqlite3VdbeJumpHere(v, jmpIfDynamic);
  }
  sqlite3ExprCachePop(pParse);

  return rReg;
}
#endif /* SQLITE_OMIT_SUBQUERY */

#ifndef SQLITE_OMIT_SUBQUERY
/*
** Expr pIn is an IN(...) expression. This function checks that the 
** sub-select on the RHS of the IN() operator has the same number of 
** columns as the vector on the LHS. Or, if the RHS of the IN() is not 
** a sub-query, that the LHS is a vector of size 1.
*/
int sqlite3ExprCheckIN(Parse *pParse, Expr *pIn){
  int nVector = sqlite3ExprVectorSize(pIn->pLeft);
  if( (pIn->flags & EP_xIsSelect) ){
    if( nVector!=pIn->x.pSelect->pEList->nExpr ){
      sqlite3SubselectError(pParse, pIn->x.pSelect->pEList->nExpr, nVector);
      return 1;
    }
  }else if( nVector!=1 ){
    if( (pIn->pLeft->flags & EP_xIsSelect) ){
      sqlite3SubselectError(pParse, nVector, 1);
    }else{
      sqlite3ErrorMsg(pParse, "invalid use of row value");
    }
    return 1;
  }
  return 0;
}
#endif

#ifndef SQLITE_OMIT_SUBQUERY
/*
** Generate code for an IN expression.
**
**      x IN (SELECT ...)
**      x IN (value, value, ...)
................................................................................
  int *aiMap = 0;       /* Map from vector field to index column */
  char *zAff = 0;       /* Affinity string for comparisons */
  int nVector;          /* Size of vectors for this IN(...) op */
  int regSelect = 0;
  Expr *pLeft = pExpr->pLeft;
  int i;

  if( sqlite3ExprCheckIN(pParse, pExpr) ) return;
  nVector = sqlite3ExprVectorSize(pExpr->pLeft);
  aiMap = (int*)sqlite3DbMallocZero(
      pParse->db, nVector*(sizeof(int) + sizeof(char)) + 1
  );
  if( !aiMap ) return;
  zAff = (char*)&aiMap[nVector];


  /* Attempt to compute the RHS. After this step, if anything other than
  ** IN_INDEX_NOOP is returned, the table opened ith cursor pExpr->iTable 
  ** contains the values that make up the RHS. If IN_INDEX_NOOP is returned,
  ** the RHS has not yet been coded.  */
  v = pParse->pVdbe;
  assert( v!=0 );       /* OOM detected prior to this routine */
................................................................................
      sqlite3VdbeAddOp2(v, OP_IsNull, regCkNull, destIfNull); VdbeCoverage(v);
      sqlite3VdbeGoto(v, destIfFalse);
    }
    sqlite3VdbeResolveLabel(v, labelOk);
    sqlite3ReleaseTempReg(pParse, regCkNull);
  }else{
  
    /* If any value on the LHS is NULL, the result of the IN(...) operator
    ** must be either false or NULL. If these two are handled identically,
    ** test the LHS for NULLs and jump directly to destIfNull if any are
    ** found. 
    **
    ** Otherwise, if NULL and false are handled differently, and the
    ** IN(...) operation is not a vector operation, and the LHS of the
    ** operator is NULL, then the result is false if the index is 

    ** completely empty, or NULL otherwise.  */
    if( destIfNull==destIfFalse ){
      for(i=0; i<nVector; i++){
        Expr *p = exprVectorField(pExpr->pLeft, i);
        if( sqlite3ExprCanBeNull(p) ){
          sqlite3VdbeAddOp2(v, OP_IsNull, r1+aiMap[i], destIfNull);
        }
      }
................................................................................
      sqlite3VdbeAddOp2(v, OP_Rewind, pExpr->iTable, destIfFalse);
      VdbeCoverage(v);
      sqlite3VdbeGoto(v, destIfNull);
      sqlite3VdbeJumpHere(v, addr1);
    }
  
    if( eType==IN_INDEX_ROWID ){
      /* In this case, the RHS is the ROWID of table b-tree */

      sqlite3VdbeAddOp3(v, OP_SeekRowid, pExpr->iTable, destIfFalse, r1);
      VdbeCoverage(v);
    }else{
      /* In this case, the RHS is an index b-tree. Apply the comparison
      ** affinities to each value on the LHS of the operator.  */
      sqlite3VdbeAddOp4(v, OP_Affinity, r1, nVector, 0, zAff, nVector);
      
      if( nVector>1 && destIfNull!=destIfFalse ){




        int iIdx = pExpr->iTable;
        int addr;
        int addrNext;


        /* Search the index for the key. */
        addr = sqlite3VdbeAddOp4Int(v, OP_Found, iIdx, 0, r1, nVector);

        /* At this point the specified key is not present in the index, 
        ** so the result of the IN(..) operator must be either NULL or
        ** 0. The vdbe code generated below figures out which.  */
        addrNext = 1+sqlite3VdbeAddOp2(v, OP_Rewind, iIdx, destIfFalse);

        for(i=0; i<nVector; i++){
          Expr *p;
          CollSeq *pColl;
          int r2 = sqlite3GetTempReg(pParse);
          p = exprVectorField(pLeft, i);
          pColl = sqlite3ExprCollSeq(pParse, p);

          sqlite3VdbeAddOp3(v, OP_Column, iIdx, i, r2);
          sqlite3VdbeAddOp4(v, OP_Eq, r1+i, 0, r2, (void*)pColl,P4_COLLSEQ);
          sqlite3VdbeChangeP5(v, SQLITE_JUMPIFNULL);

          sqlite3VdbeAddOp2(v, OP_Next, iIdx, addrNext);
          sqlite3VdbeAddOp2(v, OP_Goto, 0, destIfFalse);
          sqlite3VdbeJumpHere(v, sqlite3VdbeCurrentAddr(v)-3);
          sqlite3ReleaseTempReg(pParse, r2);
        }
        sqlite3VdbeAddOp2(v, OP_Goto, 0, destIfNull);




        /* The key was found in the index. If it contains any NULL values,
        ** then the result of the IN(...) operator is NULL. Otherwise, the
        ** result is 1.  */
        sqlite3VdbeJumpHere(v, addr);
        for(i=0; i<nVector; i++){
          Expr *p = exprVectorField(pExpr->pLeft, i);
          if( sqlite3ExprCanBeNull(p) ){
            sqlite3VdbeAddOp2(v, OP_IsNull, r1+aiMap[i], destIfNull);
          }



        }


















      }else if( rRhsHasNull==0 ){
        /* This branch runs if it is known at compile time that the RHS
        ** cannot contain NULL values. This happens as a result
        ** of "NOT NULL" constraints in the database schema.
        **
        ** Also run this branch if NULL is equivalent to FALSE
        ** for this particular IN operator.  */

        sqlite3VdbeAddOp4Int(
            v, OP_NotFound, pExpr->iTable, destIfFalse, r1, nVector
        );
        VdbeCoverage(v);
      }else{
        /* In this branch, the RHS of the IN might contain a NULL and
        ** the presence of a NULL on the RHS makes a difference in the
        ** outcome.
        */
        int addr1;

        /* First check to see if the LHS is contained in the RHS.  If so,
        ** then the answer is TRUE the presence of NULLs in the RHS does
        ** not matter.  If the LHS is not contained in the RHS, then the
        ** answer is NULL if the RHS contains NULLs and the answer is
        ** FALSE if the RHS is NULL-free.
        */
        addr1 = sqlite3VdbeAddOp4Int(v, OP_Found, pExpr->iTable, 0, r1, 1);
................................................................................
*/
int sqlite3ExprCodeTarget(Parse *pParse, Expr *pExpr, int target){
  Vdbe *v = pParse->pVdbe;  /* The VM under construction */
  int op;                   /* The opcode being coded */
  int inReg = target;       /* Results stored in register inReg */
  int regFree1 = 0;         /* If non-zero free this temporary register */
  int regFree2 = 0;         /* If non-zero free this temporary register */
  int r1, r2;               /* Various register numbers */
  sqlite3 *db = pParse->db; /* The database connection */
  Expr tempX;               /* Temporary expression node */
  int p5 = 0;

  assert( target>0 && target<=pParse->nMem );
  if( v==0 ){
    assert( pParse->db->mallocFailed );
................................................................................
    **
    ** X is stored in pExpr->pLeft.
    ** Y is stored in pExpr->pList->a[0].pExpr.
    ** Z is stored in pExpr->pList->a[1].pExpr.
    */
    case TK_BETWEEN: {
      exprCodeBetween(pParse, pExpr, target, 0, 0);
























      break;
    }
    case TK_SPAN:
    case TK_COLLATE: 
    case TK_UPLUS: {
      inReg = sqlite3ExprCodeTarget(pParse, pExpr->pLeft, target);
      break;
................................................................................
  int regFree2 = 0;
  int r1, r2;

  assert( jumpIfNull==SQLITE_JUMPIFNULL || jumpIfNull==0 );
  if( NEVER(v==0) )     return;  /* Existence of VDBE checked by caller */
  if( NEVER(pExpr==0) ) return;  /* No way this can happen */
  op = pExpr->op;
  switch( op ){
    case TK_AND: {
      int d2 = sqlite3VdbeMakeLabel(v);
      testcase( jumpIfNull==0 );
      sqlite3ExprIfFalse(pParse, pExpr->pLeft, d2,jumpIfNull^SQLITE_JUMPIFNULL);
      sqlite3ExprCachePush(pParse);
      sqlite3ExprIfTrue(pParse, pExpr->pRight, dest, jumpIfNull);
      sqlite3VdbeResolveLabel(v, d2);
................................................................................
      /* Fall thru */
    case TK_LT:
    case TK_LE:
    case TK_GT:
    case TK_GE:
    case TK_NE:
    case TK_EQ: {
      if( pExpr->pLeft->flags & EP_Vector ) goto default_expr;
      testcase( jumpIfNull==0 );
      r1 = sqlite3ExprCodeTemp(pParse, pExpr->pLeft, &regFree1);
      r2 = sqlite3ExprCodeTemp(pParse, pExpr->pRight, &regFree2);
      codeCompare(pParse, pExpr->pLeft, pExpr->pRight, op,
                  r1, r2, dest, jumpIfNull);
      assert(TK_LT==OP_Lt); testcase(op==OP_Lt); VdbeCoverageIf(v,op==OP_Lt);
      assert(TK_LE==OP_Le); testcase(op==OP_Le); VdbeCoverageIf(v,op==OP_Le);
................................................................................
      sqlite3ExprCodeIN(pParse, pExpr, destIfFalse, destIfNull);
      sqlite3VdbeGoto(v, dest);
      sqlite3VdbeResolveLabel(v, destIfFalse);
      break;
    }
#endif
    default: {
    default_expr:
      if( exprAlwaysTrue(pExpr) ){
        sqlite3VdbeGoto(v, dest);
      }else if( exprAlwaysFalse(pExpr) ){
        /* No-op */
      }else{
        r1 = sqlite3ExprCodeTemp(pParse, pExpr, &regFree1);
        sqlite3VdbeAddOp3(v, OP_If, r1, dest, jumpIfNull!=0);

  pMaskSet = &pWInfo->sMaskSet;
  pExpr = pTerm->pExpr;
  assert( pExpr->op!=TK_AS && pExpr->op!=TK_COLLATE );
  prereqLeft = sqlite3WhereExprUsage(pMaskSet, pExpr->pLeft);
  op = pExpr->op;
  if( op==TK_IN ){
    assert( pExpr->pRight==0 );

    if( ExprHasProperty(pExpr, EP_xIsSelect) ){
      pTerm->prereqRight = exprSelectUsage(pMaskSet, pExpr->x.pSelect);
    }else{
      pTerm->prereqRight = sqlite3WhereExprListUsage(pMaskSet, pExpr->x.pList);
    }
  }else if( op==TK_ISNULL ){
    pTerm->prereqRight = 0;

  pMaskSet = &pWInfo->sMaskSet;
  pExpr = pTerm->pExpr;
  assert( pExpr->op!=TK_AS && pExpr->op!=TK_COLLATE );
  prereqLeft = sqlite3WhereExprUsage(pMaskSet, pExpr->pLeft);
  op = pExpr->op;
  if( op==TK_IN ){
    assert( pExpr->pRight==0 );
    if( sqlite3ExprCheckIN(pParse, pExpr) ) return;
    if( ExprHasProperty(pExpr, EP_xIsSelect) ){
      pTerm->prereqRight = exprSelectUsage(pMaskSet, pExpr->x.pSelect);
    }else{
      pTerm->prereqRight = sqlite3WhereExprListUsage(pMaskSet, pExpr->x.pList);
    }
  }else if( op==TK_ISNULL ){
    pTerm->prereqRight = 0;

# 2016 July 29
#
# 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 implements regression tests for SQLite library.  The
# focus of this file is syntax errors involving row-value constructors
# and sub-selects that return multiple arguments.
#

set testdir [file dirname $argv0]
source $testdir/tester.tcl
set ::testprefix rowvalue4

do_execsql_test 0 {
  CREATE TABLE t1(a, b, c);
  CREATE INDEX t1bac ON t1(b, a, c);
}

foreach {tn e} {
  1 "(1, 2, 3)"
  2 "1 + (1, 2)"
  3 "(1,2,3) == (1, 2)"
} {
  do_catchsql_test 1.$tn "SELECT $e" {1 {invalid use of row value}}
}

foreach {tn s error} {
  1 "SELECT * FROM t1 WHERE a = (1, 2)"       {invalid use of row value}
  2 "SELECT * FROM t1 WHERE b = (1, 2)"       {invalid use of row value}
  3 "SELECT * FROM t1 WHERE NOT (b = (1, 2))" {invalid use of row value}
  4 "SELECT * FROM t1 LIMIT (1, 2)"           {invalid use of row value}
  5 "SELECT (a, b) IN (SELECT * FROM t1) FROM t1" 
                             {sub-select returns 3 columns - expected 2}

  6 "SELECT * FROM t1 WHERE (a, b) IN (SELECT * FROM t1)" 
                             {sub-select returns 3 columns - expected 2}
} {
  do_catchsql_test 2.$tn "$s" [list 1 $error]
}

finish_test