SQLite

**                         populated epheremal table.
**   IN_INDEX_NOOP       - No cursor was allocated.  The IN operator must be
**                         implemented as a sequence of comparisons.
**
** An existing b-tree might be used if the RHS expression pX is a simple
** subquery such as:
**
**     SELECT <column1>, <column2>... FROM <table>
**
** If the RHS of the IN operator is a list or a more complex subquery, then
** an ephemeral table might need to be generated from the RHS and then
** pX->iTable made to point to the ephemeral table instead of an
** existing table.
**
** The inFlags parameter must contain exactly one of the bits
** IN_INDEX_MEMBERSHIP or IN_INDEX_LOOP.  If inFlags contains
** IN_INDEX_MEMBERSHIP, then the generated table will be used for a
** fast membership test.  When the IN_INDEX_LOOP bit is set, the
** IN index will be used to loop over all values of the RHS of the
** IN operator.
**
** When IN_INDEX_LOOP is used (and the b-tree will be used to iterate
** through the set members) then the b-tree must not contain duplicates.
** An epheremal table must be used unless the selected columns are guaranteed
** to be unique - either because it is an INTEGER PRIMARY KEY or due to
** a UNIQUE constraint or index.
**
** When IN_INDEX_MEMBERSHIP is used (and the b-tree will be used 
** for fast set membership tests) then an epheremal table must 
** be used unless <columns> is a single INTEGER PRIMARY KEY column or an 
** index can be found with the specified <columns> as its left-most.
**
** If the IN_INDEX_NOOP_OK and IN_INDEX_MEMBERSHIP are both set and
** if the RHS of the IN operator is a list (not a subquery) then this
** routine might decide that creating an ephemeral b-tree for membership
** testing is too expensive and return IN_INDEX_NOOP.  In that case, the
** calling routine should implement the IN operator using a sequence
** of Eq or Ne comparison operations.
**
** When the b-tree is being used for membership tests, the calling function
** might need to know whether or not the RHS side of the IN operator
** contains a NULL.  If prRhsHasNull is not a NULL pointer and 
** if there is any chance that the (...) might contain a NULL value at
** runtime, then a register is allocated and the register number written
** to *prRhsHasNull. If there is no chance that the (...) contains a
** NULL value, then *prRhsHasNull is left unchanged.
**
** 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.
**
** If the aiMap parameter is not NULL, it must point to an array containing
** one element for each column returned by the SELECT statement on the RHS
** of the IN(...) operator. The i'th entry of the array is populated with the
** offset of the index column that matches the i'th column returned by the
** SELECT. For example, if the expression and selected index are:
**
**   (?,?,?) IN (SELECT a, b, c FROM t1)
**   CREATE INDEX i1 ON t1(b, c, a);
**
** then aiMap[] is populated with {2, 0, 1}.
*/
#ifndef SQLITE_OMIT_SUBQUERY
int sqlite3FindInIndex(
  Parse *pParse, 
  Expr *pX, 
  u32 inFlags, 
  int *prRhsHasNull,

    n = sqlite3ExprVectorSize(pX->pLeft);
    for(i=0; i<n; i++) aiMap[i] = i;
  }
  return eType;
}
#endif

/*
** Argument pExpr is an (?, ?...) IN(...) expression. This 
** function allocates and returns a nul-terminated string containing 
** the affinities to be used for each column of the comparison.
**
** It is the responsibility of the caller to ensure that the returned
** string is eventually freed using sqlite3DbFree().
*/
static char *exprINAffinity(Parse *pParse, Expr *pExpr){
  Expr *pLeft = pExpr->pLeft;
  int nVal = sqlite3ExprVectorSize(pLeft);
  Select *pSelect = (pExpr->flags & EP_xIsSelect) ? pExpr->x.pSelect : 0;
  char *zRet;

  assert( pExpr->op==TK_IN );
  zRet = sqlite3DbMallocZero(pParse->db, nVal+1);
  if( zRet ){
    int i;
    for(i=0; i<nVal; i++){
      Expr *pA = exprVectorField(pLeft, i);
      char a = sqlite3ExprAffinity(pA);
      if( pSelect ){
        zRet[i] = sqlite3CompareAffinity(pSelect->pEList->a[i].pExpr, a);
      }else{
        zRet[i] = a;
      }


    }
    zRet[nVal] = '\0';
  }
  return zRet;
}

#ifndef SQLITE_OMIT_SUBQUERY

    case TK_IN: {
      int addr;                   /* Address of OP_OpenEphemeral instruction */
      Expr *pLeft = pExpr->pLeft; /* the LHS of the IN operator */
      KeyInfo *pKeyInfo = 0;      /* Key information */
      int nVal;                   /* Size of vector pLeft */
      
      nVal = sqlite3ExprVectorSize(pLeft);
      assert( !isRowid || nVal==1 );

      /* Whether this is an 'x IN(SELECT...)' or an 'x IN(<exprlist>)'
      ** expression it is handled the same way.  An ephemeral table is 
      ** filled with index keys representing the results from the 
      ** SELECT or the <exprlist>.
      **
      ** If the 'x' expression is a column value, or the SELECT...
      ** statement returns a column value, then the affinity of that
      ** column is used to build the index keys. If both 'x' and the
      ** SELECT... statement are columns, then numeric affinity is used
      ** if either column has NUMERIC or INTEGER affinity. If neither
      ** 'x' nor the SELECT... statement are columns, then numeric affinity

  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 */

  Expr *pLeft = pExpr->pLeft;
  int i;

  if( sqlite3ExprCheckIN(pParse, pExpr) ) return;
  zAff = exprINAffinity(pParse, pExpr);
  nVector = sqlite3ExprVectorSize(pExpr->pLeft);
  aiMap = (int*)sqlite3DbMallocZero(
      pParse->db, nVector*(sizeof(int) + sizeof(char)) + 1
  );
  if( !zAff || !aiMap ){
    sqlite3DbFree(pParse->db, aiMap);
    return;

  }

  /* 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 */

  /* 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) ){
    int regSelect = sqlite3CodeSubselect(pParse, pLeft, 0, 0);

    for(i=0; i<nVector; i++){
      sqlite3VdbeAddOp3(v, OP_Copy, regSelect+i, r1+aiMap[i], 0);

    }


  }else{
    for(i=0; i<nVector; i++){
      Expr *pLhs = exprVectorField(pLeft, i);
      sqlite3ExprCode(pParse, pLhs, r1+aiMap[i]);







    }
  }

  /* If sqlite3FindInIndex() did not find or create an index that is
  ** suitable for evaluating the IN operator, then evaluate using a
  ** sequence of comparisons.
  */

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

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

        ** does not matter.  But there might be a LIMIT clause, in which
        ** case the order does matter */
        pushOntoSorter(pParse, pSort, p, regResult, regResult, 1, nPrefixReg);
      }else{
        int r1 = sqlite3GetTempReg(pParse);
        assert( sqlite3Strlen30(pDest->zAffSdst)==nResultCol );
        sqlite3VdbeAddOp4(v, OP_MakeRecord, regResult, nResultCol, 
            r1, pDest->zAffSdst, nResultCol);
        sqlite3ExprCacheAffinityChange(pParse, regResult, nResultCol);
        sqlite3VdbeAddOp2(v, OP_IdxInsert, iParm, r1);
        sqlite3ReleaseTempReg(pParse, r1);
      }
      break;
    }

      sqlite3VdbeChangeP5(v, OPFLAG_APPEND);
      break;
    }
#ifndef SQLITE_OMIT_SUBQUERY
    case SRT_Set: {
      assert( nColumn==sqlite3Strlen30(pDest->zAffSdst) );
      sqlite3VdbeAddOp4(v, OP_MakeRecord, regRow, nColumn, regRowid,
                        pDest->zAffSdst, nColumn);
      sqlite3ExprCacheAffinityChange(pParse, regRow, nColumn);
      sqlite3VdbeAddOp2(v, OP_IdxInsert, iParm, regRowid);
      break;
    }
    case SRT_Mem: {

      /* The LIMIT clause will terminate the loop for us */
      break;
    }
#endif
    default: {
      assert( eDest==SRT_Output || eDest==SRT_Coroutine ); 
      testcase( eDest==SRT_Output );

    }
  }
  if( pLoop->nOut > nRow-iReduce )  pLoop->nOut = nRow - iReduce;
}

/* 
** Term pTerm is a vector range comparison operation. The first comparison
** in the vector can be optimized using column nEq of the index. This
** function returns the total number of vector elements that can be used
** as part of the range comparison.
**
** For example, if the query is:
**
**   WHERE a = ? AND (b, c, d) > (?, ?, ?)
**
** and the index:
**
**   CREATE INDEX ... ON (a, b, c, d, e)
**
** then this function would be invoked with nEq=1. The value returned in
** this case is 3.
*/
int whereRangeVectorLen(
  Parse *pParse, int iCur, Index *pIdx, int nEq, WhereTerm *pTerm
){
  int nCmp = sqlite3ExprVectorSize(pTerm->pExpr->pLeft);
  int i;

        if( pIdx->aiColumn[i]>=0 ) ai[pIdx->aiColumn[i]+1] = i+1;
      }
      sqlite3VdbeChangeP4(v, -1, (char*)ai, P4_INTARRAY);
    }
  }
}

/*
** If the expression passed as the second argument is a vector, generate
** code to write the first nReg elements of the vector into an array
** of registers starting with iReg.
**
** If the expression is not a vector, then nReg must be passed 1. In
** this case, generate code to evaluate the expression and leave the
** result in register iReg.
*/
static void codeExprOrVector(Parse *pParse, Expr *p, int iReg, int nReg){
  assert( nReg>0 );
  if( sqlite3ExprIsVector(p) ){
    int i;
    if( (p->flags & EP_xIsSelect)==0 ){
      ExprList *pList = p->x.pList;
      assert( nReg<=pList->nExpr );

      if( 0==sqlite3ExprIsVector(pX->pRight) 
       && (pX->op==TK_LT || pX->op==TK_GT) 
      ){
        testOp = bRev ? OP_Le : OP_Ge;
      }else{
        testOp = bRev ? OP_Lt : OP_Gt;
      }
      if( 0==sqlite3ExprIsVector(pX->pRight) ){
        disableTerm(pLevel, pEnd);
      }
    }
    start = sqlite3VdbeCurrentAddr(v);
    pLevel->op = bRev ? OP_Prev : OP_Next;
    pLevel->p1 = iCur;
    pLevel->p2 = start;
    assert( pLevel->p5==0 );
    if( testOp!=OP_Noop ){

do_execsql_test 8.0 {
  CREATE TABLE j1(a);
}
do_execsql_test 8.1 {
  SELECT * FROM j1 WHERE (select min(a) FROM j1) IN (?, ?, ?)
}

do_execsql_test 9.0 {
  CREATE TABLE t2(a INTEGER PRIMARY KEY, b, c);
  INSERT INTO t2 VALUES(1, 1, 1);
  INSERT INTO t2 VALUES(2, 2, 2);
  INSERT INTO t2 VALUES(3, 3, 3);
  INSERT INTO t2 VALUES(4, 4, 4);
  INSERT INTO t2 VALUES(5, 5, 5);
}

foreach {tn q res} {
  1 "(a, b) > (2, 1)" {2 3 4 5}
  2 "(a, b) > (2, 2)" {3 4 5}
  3 "(a, b) < (4, 5)" {1 2 3 4}
  4 "(a, b) < (4, 3)" {1 2 3}
} {
  do_execsql_test 9.$tn "SELECT c FROM t2 WHERE $q" $res
} 


finish_test