SQLite

  if( (pExpr->flags & EP_Vector)==0 ) return 1;
  if( pExpr->flags & EP_xIsSelect ){
    return pExpr->x.pSelect->pEList->nExpr;
  }
  return pExpr->x.pList->nExpr;
}

/*
** If the expression passed as the first argument is a TK_VECTOR, return
** a pointer to the i'th field of the vector. Or, if the first argument
** points to a sub-select, return a pointer to the i'th returned column 
** value. Otherwise, return a copy of the first argument.
*/
static Expr *exprVectorField(Expr *pVector, int i){
  if( (pVector->flags & EP_Vector)==0 ){
    assert( i==0 );
    return pVector;
  }else if( pVector->flags & EP_xIsSelect ){
    return pVector->x.pSelect->pEList->a[i].pExpr;
  }

/*
** pX is the RHS of an IN operator.  If pX is a SELECT statement 
** that can be simplified to a direct table access, then return
** a pointer to the SELECT statement.  If pX is not a SELECT statement,
** or if the SELECT statement needs to be manifested into a transient
** table, then return NULL.
** 
** If parameter bNullSensitive is 0, then this operation will be
** 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;

**
** If a register is allocated and its location stored in *prRhsHasNull, then
** the value in that register will be NULL if the b-tree contains one or more
** NULL values, and it will be some non-NULL value if the b-tree contains no
** NULL values.
*/
#ifndef SQLITE_OMIT_SUBQUERY
int sqlite3FindInIndex(
  Parse *pParse, 
  Expr *pX, 
  u32 inFlags, 
  int *prRhsHasNull,
  int *aiMap
){
  Select *p;                            /* SELECT to the right of IN operator */
  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) */
    assert( p->pEList->a[0].pExpr!=0 ); /* Because of isCandidateForInOpt(p) */
    assert( p->pSrc!=0 );               /* Because of isCandidateForInOpt(p) */
    pTab = p->pSrc->a[0].pTab;

    /* Code an OP_Transaction and OP_TableLock for <table>. */

          for(j=0; j<nExpr; j++){
            if( pIdx->aiColumn[j]!=pRhs->iColumn ) continue;
            assert( pIdx->azColl[j] );
            if( sqlite3StrICmp(pReq->zName, pIdx->azColl[j])!=0 ) continue;
            break;
          }
          if( j==nExpr ) break;
          if( aiMap ) aiMap[i] = j;
        }

        if( i==nExpr ){
          int iAddr = sqlite3CodeOnce(pParse); VdbeCoverage(v);
          sqlite3VdbeAddOp3(v, OP_OpenRead, iTab, pIdx->tnum, iDb);
          sqlite3VdbeSetP4KeyInfo(pParse, pIdx);
          VdbeComment((v, "%s", pIdx->zName));

      *prRhsHasNull = rMayHaveNull = ++pParse->nMem;
    }
    sqlite3CodeSubselect(pParse, pX, rMayHaveNull, eType==IN_INDEX_ROWID);
    pParse->nQueryLoop = savedNQueryLoop;
  }else{
    pX->iTable = iTab;
  }

  if( aiMap && eType!=IN_INDEX_INDEX_ASC && eType!=IN_INDEX_INDEX_DESC ){
    int i, n;
    n = sqlite3ExprVectorSize(pX->pLeft);
    for(i=0; i<n; i++) aiMap[i] = i;
  }
  return eType;
}
#endif

static char *exprINAffinity(Parse *pParse, Expr *pExpr){
  Expr *pLeft = pExpr->pLeft;
  int nVal = sqlite3ExprVectorSize(pLeft);

  }
  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, ...)
**

static void sqlite3ExprCodeIN(
  Parse *pParse,        /* Parsing and code generating context */
  Expr *pExpr,          /* The IN expression */
  int destIfFalse,      /* Jump here if LHS is not contained in the RHS */
  int destIfNull        /* Jump here if the results are unknown due to NULLs */
){
  int rRhsHasNull = 0;  /* Register that is true if RHS contains NULL values */

  int eType;            /* Type of the RHS */
  int r1;               /* Temporary use register */
  Vdbe *v;              /* Statement under construction */
  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 */
  VdbeNoopComment((v, "begin IN expr"));
  eType = sqlite3FindInIndex(pParse, pExpr,
                             IN_INDEX_MEMBERSHIP | IN_INDEX_NOOP_OK,
                             destIfFalse==destIfNull ? 0 : &rRhsHasNull, aiMap);

  assert( pParse->nErr || nVector==1 || eType==IN_INDEX_EPH
       || eType==IN_INDEX_INDEX_ASC || eType==IN_INDEX_INDEX_DESC 


  );

  /* Code the LHS, the <expr> from "<expr> IN (...)". If the LHS is a 
  ** vector, then it is stored in an array of nVector registers starting 
  ** at r1.
  */
  r1 = sqlite3GetTempRange(pParse, nVector);
  sqlite3ExprCachePush(pParse);
  if( nVector>1 && (pLeft->flags & EP_xIsSelect) ){
    regSelect = sqlite3CodeSubselect(pParse, pLeft, 0, 0);
  }
  for(i=0; i<nVector; i++){
    int iCol = aiMap[i];
    Expr *pLhs = exprVectorField(pLeft, i);

    if( regSelect ){
      sqlite3VdbeAddOp3(v, OP_Copy, regSelect+i, r1+iCol, 0);
    }else{
      sqlite3ExprCode(pParse, pLhs, r1+iCol);
    }

    zAff[iCol] = sqlite3ExprAffinity(pLhs);
    if( pExpr->flags & EP_xIsSelect ){
      zAff[iCol] = sqlite3CompareAffinity(
          pExpr->x.pSelect->pEList->a[iCol].pExpr, zAff[iCol]
      );
    }
  }

  /* If sqlite3FindInIndex() did not find or create an index that is
  ** suitable for evaluating the IN operator, then evaluate using a
  ** sequence of comparisons.
  */
  if( eType==IN_INDEX_NOOP ){
    ExprList *pList = pExpr->x.pList;

        sqlite3VdbeAddOp3(v, OP_BitAnd, regCkNull, r2, regCkNull);
      }
      if( ii<pList->nExpr-1 || destIfNull!=destIfFalse ){
        sqlite3VdbeAddOp4(v, OP_Eq, r1, labelOk, r2,
                          (void*)pColl, P4_COLLSEQ);
        VdbeCoverageIf(v, ii<pList->nExpr-1);
        VdbeCoverageIf(v, ii==pList->nExpr-1);
        sqlite3VdbeChangeP5(v, zAff[0]);
      }else{
        assert( destIfNull==destIfFalse );
        sqlite3VdbeAddOp4(v, OP_Ne, r1, destIfFalse, r2,
                          (void*)pColl, P4_COLLSEQ); VdbeCoverage(v);
        sqlite3VdbeChangeP5(v, zAff[0] | SQLITE_JUMPIFNULL);
      }
      sqlite3ReleaseTempReg(pParse, regToFree);
    }
    if( regCkNull ){
      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( nVector==1 && sqlite3ExprCanBeNull(pExpr->pLeft) ){
      if( destIfNull==destIfFalse ){
        /* Shortcut for the common case where the false and NULL outcomes are
        ** the same. */
        sqlite3VdbeAddOp2(v, OP_IsNull, r1, destIfNull); VdbeCoverage(v);
      }else{
        int addr1 = sqlite3VdbeAddOp1(v, OP_NotNull, r1); VdbeCoverage(v);
        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 ){
      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;

        sqlite3VdbeGoto(v, destIfFalse);
        sqlite3VdbeJumpHere(v, addr1);
      }
    }
  }
  sqlite3ReleaseTempReg(pParse, r1);
  sqlite3ExprCachePop(pParse);
  sqlite3DbFree(pParse->db, aiMap);
  VdbeComment((v, "end IN expr"));
}
#endif /* SQLITE_OMIT_SUBQUERY */

#ifndef SQLITE_OMIT_FLOATING_POINT
/*
** Generate an instruction that will put the floating point

  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: {
      testcase( jumpIfNull==0 );
      sqlite3ExprIfFalse(pParse, pExpr->pLeft, dest, jumpIfNull);
      sqlite3ExprCachePush(pParse);
      sqlite3ExprIfFalse(pParse, pExpr->pRight, dest, jumpIfNull);
      sqlite3ExprCachePop(pParse);
      break;

      /* 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, dest, destIfNull);
        sqlite3VdbeResolveLabel(v, destIfNull);
      }
      break;
    }
#endif
    default: {
    default_expr: 
      if( exprAlwaysFalse(pExpr) ){
        sqlite3VdbeGoto(v, dest);
      }else if( exprAlwaysTrue(pExpr) ){
        /* no-op */
      }else{
        r1 = sqlite3ExprCodeTemp(pParse, pExpr, &regFree1);
        sqlite3VdbeAddOp3(v, OP_IfNot, r1, dest, jumpIfNull!=0);

#define IN_INDEX_NOOP         5   /* No table available. Use comparisons */
/*
** Allowed flags for the 3rd parameter to sqlite3FindInIndex().
*/
#define IN_INDEX_NOOP_OK     0x0001  /* OK to return IN_INDEX_NOOP */
#define IN_INDEX_MEMBERSHIP  0x0002  /* IN operator used for membership test */
#define IN_INDEX_LOOP        0x0004  /* IN operator used as a loop */
int sqlite3FindInIndex(Parse *, Expr *, u32, int*, int*);

int sqlite3JournalOpen(sqlite3_vfs *, const char *, sqlite3_file *, int, int);
int sqlite3JournalSize(sqlite3_vfs *);
#ifdef SQLITE_ENABLE_ATOMIC_WRITE
  int sqlite3JournalCreate(sqlite3_file *);
#endif

    ){
      testcase( iEq==0 );
      testcase( bRev );
      bRev = !bRev;
    }
    assert( pX->op==TK_IN );
    iReg = iTarget;
    eType = sqlite3FindInIndex(pParse, pX, IN_INDEX_LOOP, 0, 0);
    if( eType==IN_INDEX_INDEX_DESC ){
      testcase( bRev );
      bRev = !bRev;
    }
    iTab = pX->iTable;
    sqlite3VdbeAddOp2(v, bRev ? OP_Last : OP_Rewind, iTab, 0);
    VdbeCoverageIf(v, bRev);

# 2016 June 17
#
# 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 testing "(...) IN (SELECT ...)" expressions
# where the SELECT statement returns more than one column.
#

set testdir [file dirname $argv0]
source $testdir/tester.tcl
set ::testprefix rowvalue3


do_execsql_test 1.0 {
  CREATE TABLE t1(a, b, c);
  CREATE INDEX i1 ON t1(a, b);
  INSERT INTO t1 VALUES(1, 2, 3);
  INSERT INTO t1 VALUES(4, 5, 6);
  INSERT INTO t1 VALUES(7, 8, 9);
}

foreach {tn sql res} {
  1  "SELECT 1 WHERE (4, 5) IN (SELECT a, b FROM t1)"  1
  2  "SELECT 1 WHERE (5, 5) IN (SELECT a, b FROM t1)"  {}
  3  "SELECT 1 WHERE (5, 4) IN (SELECT a, b FROM t1)"  {}
  4  "SELECT 1 WHERE (5, 4) IN (SELECT b, a FROM t1)"  1
  5  "SELECT 1 WHERE (SELECT a, b FROM t1 WHERE c=6) IN (SELECT a, b FROM t1)" 1
  6  "SELECT (5, 4) IN (SELECT a, b FROM t1)" 0
  7  "SELECT 1 WHERE (5, 4) IN (SELECT +b, +a FROM t1)"  1
  8  "SELECT (5, 4) IN (SELECT +b, +a FROM t1)"  1
  9  "SELECT (1, 2) IN (SELECT rowid, b FROM t1)"  1
  10 "SELECT 1 WHERE (1, 2) IN (SELECT rowid, b FROM t1)"  1
  11 "SELECT 1 WHERE (1, NULL) IN (SELECT rowid, b FROM t1)"  {}
} {
  do_execsql_test 1.$tn $sql $res
}

#explain_i { SELECT (4, NULL) IN (SELECT a, b FROM t1) } 
#do_execsql_test 2 { SELECT (4, NULL) IN (SELECT a, b FROM t1) } {}




finish_test