**    May you share freely, never taking more than you give.
**
*************************************************************************
** This module contains C code that generates VDBE code used to process
** the WHERE clause of SQL statements.  Also found here are subroutines
** to generate VDBE code to evaluate expressions.
**
** $Id: where.c,v 1.61 2002/08/13 23:02:58 drh Exp $
*/
#include "sqliteInt.h"

/*
** The query generator uses an array of instances of this structure to
** help it analyze the subexpressions of the WHERE clause.  Each WHERE
** clause subexpression is separated from the others by an AND operator.
................................................................................
  assert( pOrderBy!=0 );
  assert( pOrderBy->nExpr>0 );
  for(i=0; i<pOrderBy->nExpr; i++){
    Expr *p;
    if( (pOrderBy->a[i].sortOrder & SQLITE_SO_DIRMASK)!=SQLITE_SO_ASC ){
      /* Indices can only be used for ascending sort order */
      return 0;




    }
    p = pOrderBy->a[i].pExpr;
    if( p->op!=TK_COLUMN || p->iTable!=base ){
      /* Can not use an index sort on anything that is not a column in the
      ** left-most table of the FROM clause */
      return 0;
    }

**    May you share freely, never taking more than you give.
**
*************************************************************************
** This module contains C code that generates VDBE code used to process
** the WHERE clause of SQL statements.  Also found here are subroutines
** to generate VDBE code to evaluate expressions.
**
** $Id: where.c,v 1.62 2002/08/14 03:03:57 drh Exp $
*/
#include "sqliteInt.h"

/*
** The query generator uses an array of instances of this structure to
** help it analyze the subexpressions of the WHERE clause.  Each WHERE
** clause subexpression is separated from the others by an AND operator.
................................................................................
  assert( pOrderBy!=0 );
  assert( pOrderBy->nExpr>0 );
  for(i=0; i<pOrderBy->nExpr; i++){
    Expr *p;
    if( (pOrderBy->a[i].sortOrder & SQLITE_SO_DIRMASK)!=SQLITE_SO_ASC ){
      /* Indices can only be used for ascending sort order */
      return 0;
    }
    if( (pOrderBy->a[i].sortOrder & SQLITE_SO_TYPEMASK)!=SQLITE_SO_UNK ){
      /* Do not sort by index if there is a COLLATE clause */
      return 0;
    }
    p = pOrderBy->a[i].pExpr;
    if( p->op!=TK_COLUMN || p->iTable!=base ){
      /* Can not use an index sort on anything that is not a column in the
      ** left-most table of the FROM clause */
      return 0;
    }

#    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 the use of indices in WHERE clases.
#
# $Id: where.test,v 1.9 2002/06/19 14:27:06 drh Exp $

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

# Build some test data
#
do_test where-1.0 {
................................................................................
  }
} {1 0 2 1 3 1 nosort}
do_test where-6.16 {
  cksort {
    SELECT t3.a, t1.x FROM t3, t1 WHERE t3.a=t1.w ORDER BY t1.x, t3.a LIMIT 3
  }
} {1 0 2 1 3 1 sort}


















finish_test

#    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 the use of indices in WHERE clases.
#
# $Id: where.test,v 1.10 2002/08/14 03:03:58 drh Exp $

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

# Build some test data
#
do_test where-1.0 {
................................................................................
  }
} {1 0 2 1 3 1 nosort}
do_test where-6.16 {
  cksort {
    SELECT t3.a, t1.x FROM t3, t1 WHERE t3.a=t1.w ORDER BY t1.x, t3.a LIMIT 3
  }
} {1 0 2 1 3 1 sort}
do_test where-6.17 {
  cksort {
    SELECT y FROM t1 ORDER BY w COLLATE text LIMIT 3;
  }
} {4 121 10201 sort}
do_test where-6.18 {
  cksort {
    SELECT y FROM t1 ORDER BY w COLLATE numeric LIMIT 3;
  }
} {4 9 16 sort}
do_test where-6.19 {
  cksort {
    SELECT y FROM t1 ORDER BY w LIMIT 3;
  }
} {4 9 16 nosort}



finish_test

#
# Run this script to generated a datatypes.html output file
#
set rcsid {$Id: datatypes.tcl,v 1.1 2002/08/14 00:08:13 drh Exp $}

puts {<html>
<head>
  <title>Datatypes In SQLite</title>
</head>
<body bgcolor="white">
<h1 align="center">
................................................................................
sqlite&gt; SELECT typeof('abc'+123);
numeric
sqlite&gt; SELECT typeof('abc'||123);
text
</pre></blockquote>

<p>
For table columns, the datatype is determined by the datatype declaration
of the CREATE TABLE statement.  The datatype is text if and only if
the type declaration contains one or more of the following strings:
</p>

<blockquote>
BLOB<br>
CHAR<br>

#
# Run this script to generated a datatypes.html output file
#
set rcsid {$Id: datatypes.tcl,v 1.2 2002/08/14 03:03:58 drh Exp $}

puts {<html>
<head>
  <title>Datatypes In SQLite</title>
</head>
<body bgcolor="white">
<h1 align="center">
................................................................................
sqlite&gt; SELECT typeof('abc'+123);
numeric
sqlite&gt; SELECT typeof('abc'||123);
text
</pre></blockquote>

<p>
For table columns, the datatype is determined by the type declaration
of the CREATE TABLE statement.  The datatype is text if and only if
the type declaration contains one or more of the following strings:
</p>

<blockquote>
BLOB<br>
CHAR<br>