SQLite

** This module contains C code that generates VDBE code used to process
** the WHERE clause of SQL statements.  This module is reponsible for
** generating the code that loops through a table looking for applicable
** rows.  Indices are selected and used to speed the search when doing
** so is applicable.  Because this module is responsible for selecting
** indices, you might also think of this module as the "query optimizer".
**
** $Id: where.c,v 1.250 2007/06/02 07:54:38 danielk1977 Exp $
*/
#include "sqliteInt.h"

/*
** The number of bits in a Bitmask.  "BMS" means "BitMask Size".
*/
#define BMS  (sizeof(Bitmask)*8)

        Expr *pX;
        int k = pIdx->aiColumn[j];
        pTerm = findTerm(&wc, iCur, k, notReady, topOp, pIdx);
        assert( pTerm!=0 );
        pX = pTerm->pExpr;
        assert( (pTerm->flags & TERM_CODED)==0 );
        sqlite3ExprCode(pParse, pX->pRight);
        sqlite3VdbeAddOp(v, OP_IsNull, -(nEq*2+1), nxt);
        topEq = pTerm->eOperator & (WO_LE|WO_GE);
        disableTerm(pLevel, pTerm);
        testOp = OP_IdxGE;
      }else{
        testOp = nEq>0 ? OP_IdxGE : OP_Noop;
        topEq = 1;
      }

# This file implements regression tests for SQLite library.  The
# focus of this file is testing the use of indices in WHERE clauses.
# This file was created when support for optimizing IS NULL phrases
# was added.  And so the principle purpose of this file is to test
# that IS NULL phrases are correctly optimized.  But you can never
# have too many tests, so some other tests are thrown in as well.
#
# $Id: where4.test,v 1.4 2007/06/02 07:54:38 danielk1977 Exp $

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

# Build some test data
#
do_test where4-1.0 {

  }
  execsql {
    SELECT * FROM t6 WHERE y=NULL AND z IN ('hello');
  }
} {}

integrity_check {where4-99.0}

do_test where4-7.1 {
  execsql {
    BEGIN;
    CREATE TABLE t8(a, b, c, d);
    CREATE INDEX t8_i ON t8(a, b, c);
    CREATE TABLE t7(i);

    INSERT INTO t7 VALUES(1);
    INSERT INTO t7 SELECT i*2 FROM t7;
    INSERT INTO t7 SELECT i*2 FROM t7;
    INSERT INTO t7 SELECT i*2 FROM t7;
    INSERT INTO t7 SELECT i*2 FROM t7;
    INSERT INTO t7 SELECT i*2 FROM t7;
    INSERT INTO t7 SELECT i*2 FROM t7;

    COMMIT;
  }
} {}

# At one point the sub-select inside the aggregate sum() function in the
# following query was leaking a couple of stack entries. This query 
# runs the SELECT in a loop enough times that an assert() fails. Or rather,
# did fail before the bug was fixed.
#
do_test where4-7.2 {
  execsql {
    SELECT sum((
      SELECT d FROM t8 WHERE a = i AND b = i AND c < NULL
    )) FROM t7;
  }
} {{}}

finish_test