SQLite

**    May you find forgiveness for yourself and forgive others.
**    May you share freely, never taking more than you give.
**
*************************************************************************
** This file contains routines used for analyzing expressions and
** for generating VDBE code that evaluates expressions in SQLite.
**
** $Id: expr.c,v 1.66 2002/05/31 15:51:25 drh Exp $
*/
#include "sqliteInt.h"


/*
** Construct a new expression node and return a pointer to it.  Memory
** for this node is obtained from sqliteMalloc().  The calling function

    }
    case TK_AS: {
      sqliteExprCode(pParse, pExpr->pLeft);
      break;
    }
    case TK_CASE: {
      int expr_end_label;

      int jumpInst;

      int addr;
      int nExpr;
      int i;

      assert(pExpr->pList);
      assert((pExpr->pList->nExpr % 2) == 0);
      assert(pExpr->pList->nExpr > 0);
      nExpr = pExpr->pList->nExpr;
      expr_end_label = sqliteVdbeMakeLabel(v);

      if( pExpr->pLeft ){
        sqliteExprCode(pParse, pExpr->pLeft);

      }
      for(i=0; i<nExpr; i=i+2){
        sqliteExprCode(pParse, pExpr->pList->a[i].pExpr);

        if( pExpr->pLeft ){
          sqliteVdbeAddOp(v, OP_Dup, 1, 1);
          jumpInst = sqliteVdbeAddOp(v, OP_Ne, 1, 0);
          sqliteVdbeAddOp(v, OP_Pop, 1, 0);
        }else{
          jumpInst = sqliteVdbeAddOp(v, OP_IfNot, 1, 0);
        }
        sqliteExprCode(pParse, pExpr->pList->a[i+1].pExpr);
        sqliteVdbeAddOp(v, OP_Goto, 0, expr_end_label);








        addr = sqliteVdbeCurrentAddr(v);
        sqliteVdbeChangeP2(v, jumpInst, addr);
      }
      if( pExpr->pLeft ){
        sqliteVdbeAddOp(v, OP_Pop, 1, 0);
      }
      if( pExpr->pRight ){
        sqliteExprCode(pParse, pExpr->pRight);
      }else{
        sqliteVdbeAddOp(v, OP_String, 0, 0);
      }
      sqliteVdbeResolveLabel(v, expr_end_label);





    }
    break;
  }
}

/*
** Generate code for a boolean expression such that a jump is made

** This file contains the C functions that implement various SQL
** functions of SQLite.  
**
** There is only one exported symbol in this file - the function
** sqliteRegisterBuildinFunctions() found at the bottom of the file.
** All other code has file scope.
**
** $Id: func.c,v 1.19 2002/05/31 15:51:25 drh Exp $
*/
#include <ctype.h>
#include <math.h>
#include <stdlib.h>
#include <assert.h>
#include "sqliteInt.h"

/*
** Routines to implement min() and max() aggregate functions.
*/
static void minStep(sqlite_func *context, int argc, const char **argv){
  MinMaxCtx *p;
  p = sqlite_aggregate_context(context, sizeof(*p));
  if( p==0 || argc<1 || argv[0]==0 ) return;
  if( p->z==0 || sqliteCompare(argv[0],p->z)<0 ){
    int len;
    if( p->z && p->z!=p->zBuf ){
      sqliteFree(p->z);
    }
    len = strlen(argv[0]);
    if( len < sizeof(p->zBuf) ){
      p->z = p->zBuf;
    }else{
      p->z = sqliteMalloc( len+1 );
      if( p->z==0 ) return;
    }
    strcpy(p->z, argv[0]);
  }
}
static void maxStep(sqlite_func *context, int argc, const char **argv){
  MinMaxCtx *p;
  p = sqlite_aggregate_context(context, sizeof(*p));
  if( p==0 || argc<1 || argv[0]==0 ) return;
  if( p->z==0 || sqliteCompare(argv[0],p->z)>0 ){
    int len;
    if( p->z && p->z!=p->zBuf ){
      sqliteFree(p->z);
    }
    len = strlen(argv[0]);
    if( len < sizeof(p->zBuf) ){
      p->z = p->zBuf;

**    May you find forgiveness for yourself and forgive others.
**    May you share freely, never taking more than you give.
**
*************************************************************************
** This file contains C code routines that are called by the parser
** to handle SELECT statements in SQLite.
**
** $Id: select.c,v 1.89 2002/05/31 15:51:25 drh Exp $
*/
#include "sqliteInt.h"

/*
** Allocate a new Select structure and return a pointer to that
** structure.
*/

  }

  /* If the DISTINCT keyword was present on the SELECT statement
  ** and this row has been seen before, then do not make this row
  ** part of the result.
  */
  if( distinct>=0 && pEList && pEList->nExpr>0 ){
    /* For the purposes of the DISTINCT keyword to a SELECT, NULLs
    ** are indistinct.  This was confirmed by experiment in Oracle
    ** and PostgreSQL.  It seems contradictory, but it appears to be
    ** true.
    ** sqliteVdbeAddOp(v, OP_IsNull, -pEList->nExpr,sqliteVdbeCurrentAddr(v)+7);
    */
    sqliteVdbeAddOp(v, OP_MakeKey, pEList->nExpr, 1);
    sqliteVdbeAddOp(v, OP_Distinct, distinct, sqliteVdbeCurrentAddr(v)+3);
    sqliteVdbeAddOp(v, OP_Pop, pEList->nExpr+1, 0);
    sqliteVdbeAddOp(v, OP_Goto, 0, iContinue);
    sqliteVdbeAddOp(v, OP_String, 0, 0);
    sqliteVdbeAddOp(v, OP_PutStrKey, distinct, 0);
  }

    sqliteVdbeAddOp(v, OP_SortPut, 0, 0);
  }else 

  /* In this mode, write each query result to the key of the temporary
  ** table iParm.
  */
  if( eDest==SRT_Union ){
    sqliteVdbeAddOp(v, OP_MakeRecord, nColumn, 0);
    sqliteVdbeAddOp(v, OP_String, 0, 0);
    sqliteVdbeAddOp(v, OP_PutStrKey, iParm, 0);
  }else 

  /* Store the result as data using a unique key.
  */
  if( eDest==SRT_Table || eDest==SRT_TempTable ){
    sqliteVdbeAddOp(v, OP_MakeRecord, nColumn, 0);
    sqliteVdbeAddOp(v, OP_NewRecno, iParm, 0);
    sqliteVdbeAddOp(v, OP_Pull, 1, 0);
    sqliteVdbeAddOp(v, OP_PutIntKey, iParm, 0);
  }else 

  /* Construct a record from the query result, but instead of
  ** saving that record, use it as a key to delete elements from
  ** the temporary table iParm.
  */
  if( eDest==SRT_Except ){
    int addr = sqliteVdbeAddOp(v, OP_MakeRecord, nColumn, 0);
    sqliteVdbeAddOp(v, OP_NotFound, iParm, addr+3);
    sqliteVdbeAddOp(v, OP_Delete, iParm, 0);
  }else 

  /* If we are creating a set for an "expr IN (SELECT ...)" construct,
  ** then there should be a single item on the stack.  Write this
  ** item into the set table with bogus data.

**
*************************************************************************
** Utility functions used throughout sqlite.
**
** This file contains functions for allocating memory, comparing
** strings, and stuff like that.
**
** $Id: util.c,v 1.45 2002/05/31 15:51:25 drh Exp $
*/
#include "sqliteInt.h"
#include <stdarg.h>
#include <ctype.h>

/*
** If malloc() ever fails, this global variable gets set to 1.

*/
int sqliteSortCompare(const char *a, const char *b){
  int len;
  int res = 0;
  int isNumA, isNumB;

  while( res==0 && *a && *b ){
    if( a[1]==0 ){
      res = -1;
      break;
    }else if( b[1]==0 ){
      res = +1;
      break;
    }
    isNumA = sqliteIsNumber(&a[1]);
    isNumB = sqliteIsNumber(&b[1]);
    if( isNumA ){
      double rA, rB;
      if( !isNumB ){
        res = -1;
        break;

** type to the other occurs as necessary.
** 
** Most of the code in this file is taken up by the sqliteVdbeExec()
** function which does the work of interpreting a VDBE program.
** But other routines are also provided to help in building up
** a program instruction by instruction.
**
** $Id: vdbe.c,v 1.151 2002/05/31 15:51:26 drh Exp $
*/
#include "sqliteInt.h"
#include <ctype.h>

/*
** The following global variable is incremented every time a cursor
** moves, either by the OP_MoveTo or the OP_Next opcode.  The test

case OP_Multiply:
case OP_Divide:
case OP_Remainder: {
  int tos = p->tos;
  int nos = tos - 1;
  VERIFY( if( nos<0 ) goto not_enough_stack; )
  if( ((aStack[tos].flags | aStack[nos].flags) & STK_Null)!=0 ){
    int resultType = STK_Null;
    if( pOp->opcode==OP_Multiply ){
      /* Special case: multiplying NULL by zero gives a zero result, not a
      ** NULL result as it would normally. */
      if( (aStack[tos].flags & (STK_Int|STK_Real))!=0
              || ((aStack[tos].flags & STK_Str)!=0 && isNumber(zStack[tos])) ){
        Integerify(p,tos);
        if( aStack[tos].i==0 ){
          resultType = STK_Int;
          aStack[nos].i = 0;
        }
      }else if( (aStack[nos].flags & (STK_Int|STK_Real))!=0
              || ((aStack[nos].flags & STK_Str)!=0 && isNumber(zStack[nos])) ){
        Integerify(p,nos);
        if( aStack[nos].i==0 ){
          resultType = STK_Int;
        }
      }
    }
    POPSTACK;
    Release(p, nos);
    aStack[nos].flags = resultType;
  }else if( (aStack[tos].flags & aStack[nos].flags & STK_Int)==STK_Int ){
    int a, b;
    a = aStack[tos].i;
    b = aStack[nos].i;
    switch( pOp->opcode ){
      case OP_Add:         b += a;       break;
      case OP_Subtract:    b -= a;       break;

** that go into building the record is NULL, then add some extra
** bytes to the record to make it distinct for other entries created
** during the same run of the VDBE.  The extra bytes added are a
** counter that is reset with each run of the VDBE, so records
** created this way will not necessarily be distinct across runs.
** But they should be distinct for transient tables (created using
** OP_OpenTemp) which is what they are intended for.
**
** (Later:) The P2==1 option was intended to make NULLs distinct
** for the UNION operator.  But I have since discovered that NULLs
** are indistinct for UNION.  So this option is never used.
*/
case OP_MakeRecord: {
  char *zNewRecord;
  int nByte;
  int nField;
  int i, j;
  int idxWidth;

# 2001 September 15
#
# 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 expressions.
#
# $Id: expr.test,v 1.24 2002/05/31 15:51:26 drh Exp $

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

# Create a table to work with.
#
execsql {CREATE TABLE test1(i1 int, i2 int, r1 real, r2 real, t1 text, t2 text)}

test_expr expr-6.66 {t1='ac', t2=NULL} {t1 NOT GLOB t2} {{}}

test_expr expr-case.1 {i1=1, i2=2} \
	{CASE WHEN i1 = i2 THEN 'eq' ELSE 'ne' END} ne
test_expr expr-case.2 {i1=2, i2=2} \
	{CASE WHEN i1 = i2 THEN 'eq' ELSE 'ne' END} eq
test_expr expr-case.3 {i1=NULL, i2=2} \
	{CASE WHEN i1 = i2 THEN 'eq' ELSE 'ne' END} ne
test_expr expr-case.4 {i1=2, i2=NULL} \
	{CASE WHEN i1 = i2 THEN 'eq' ELSE 'ne' END} ne
test_expr expr-case.5 {i1=2} \
	{CASE i1 WHEN 1 THEN 'one' WHEN 2 THEN 'two' ELSE 'error' END} two
test_expr expr-case.6 {i1=1} \
	{CASE i1 WHEN 1 THEN 'one' WHEN NULL THEN 'two' ELSE 'error' END} one
test_expr expr-case.7 {i1=2} \
	{CASE i1 WHEN 1 THEN 'one' WHEN NULL THEN 'two' ELSE 'error' END} error
test_expr expr-case.8 {i1=3} \
	{CASE i1 WHEN 1 THEN 'one' WHEN NULL THEN 'two' ELSE 'error' END} error
test_expr expr-case.9 {i1=3} \
	{CASE i1 WHEN 1 THEN 'one' WHEN 2 THEN 'two' ELSE 'error' END} error
test_expr expr-case.10 {i1=3} \
	{CASE i1 WHEN 1 THEN 'one' WHEN 2 THEN 'two' END} {{}}
test_expr expr-case.11 {i1=null} \
	{CASE i1 WHEN 1 THEN 'one' WHEN 2 THEN 'two' ELSE 3 END} 3
test_expr expr-case.12 {i1=1} \
	{CASE i1 WHEN 1 THEN null WHEN 2 THEN 'two' ELSE 3 END} {{}}
test_expr expr-case.13 {i1=7} \
	{ CASE WHEN i1 < 5 THEN 'low' 
	       WHEN i1 < 10 THEN 'medium' 
               WHEN i1 < 15 THEN 'high' ELSE 'error' END} medium

#
#***********************************************************************
# This file implements regression tests for SQLite library.  The
# focus of this file is testing SELECT statements that contain
# aggregate min() and max() functions and which are handled as
# as a special case.
#
# $Id: minmax.test,v 1.4 2002/05/31 15:51:26 drh Exp $

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

do_test minmax-1.0 {
  execsql {
    BEGIN;

do_test minmax-4.1 {
  execsql {
    SELECT coalesce(min(x),-1), coalesce(max(x),-1) FROM
      (SELECT * FROM t1 UNION SELECT NULL as 'x', NULL as 'y')
  }
} {1 20}
do_test minmax-4.2 {
  execsql {
    SELECT y, sum(x) FROM
      (SELECT null, y+1 FROM t1 UNION SELECT * FROM t1)
    GROUP BY y ORDER BY y;
  }
} {1 1 2 5 3 22 4 92 5 90 6 0}
do_test minmax-4.3 {
  execsql {
    SELECT y, count(x), count(*) FROM
      (SELECT null, y+1 FROM t1 UNION SELECT * FROM t1)
    GROUP BY y ORDER BY y;
  }
} {1 1 1 2 2 3 3 4 5 4 8 9 5 5 6 6 0 1}

finish_test

# 2001 September 15
#
# 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.
#
# This file implements tests for proper treatment of the special
# value NULL.
#

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

# Create a table and some data to work with.
#
do_test null-1.0 {
  execsql {
    begin;
    create table t1(a,b,c);
    insert into t1 values(1,0,0);
    insert into t1 values(2,0,1);
    insert into t1 values(3,1,0);
    insert into t1 values(4,1,1);
    insert into t1 values(5,null,0);
    insert into t1 values(6,null,1);
    insert into t1 values(7,null,null);
    commit;
    select * from t1;
  }
} {1 0 0 2 0 1 3 1 0 4 1 1 5 {} 0 6 {} 1 7 {} {}}

# Check for how arithmetic expressions handle NULL
#
do_test null-1.1 {
  execsql {
    select ifnull(a+b,99) from t1;
  }
} {1 2 4 5 99 99 99}
do_test null-1.2 {
  execsql {
    select ifnull(b*c,99) from t1;
  }
} {0 0 0 1 0 99 99}
do_test null-1.2.1 {
  execsql {
    select ifnull(c*b,99) from t1;
  }
} {0 0 0 1 0 99 99}

# Check to see how the CASE expression handles NULL values.  The
# first WHEN for which the test expression is TRUE is selected.
# FALSE and UNKNOWN test expressions are skipped.
#
do_test null-2.1 {
  execsql {
    select ifnull(case when b<>0 then 1 else 0 end, 99) from t1;
  }
} {0 0 1 1 0 0 0}
do_test null-2.2 {
  execsql {
    select ifnull(case when not b<>0 then 1 else 0 end, 99) from t1;
  }
} {1 1 0 0 0 0 0}
do_test null-2.3 {
  execsql {
    select ifnull(case when b<>0 and c<>0 then 1 else 0 end, 99) from t1;
  }
} {0 0 0 1 0 0 0}
do_test null-2.4 {
  execsql {
    select ifnull(case when not (b<>0 and c<>0) then 1 else 0 end, 99) from t1;
  }
} {1 1 1 0 1 0 0}
do_test null-2.5 {
  execsql {
    select ifnull(case when b<>0 or c<>0 then 1 else 0 end, 99) from t1;
  }
} {0 1 1 1 0 1 0}
do_test null-2.6 {
  execsql {
    select ifnull(case when not (b<>0 or c<>0) then 1 else 0 end, 99) from t1;
  }
} {1 0 0 0 0 0 0}
do_test null-2.7 {
  execsql {
    select ifnull(case b when c then 1 else 0 end, 99) from t1;
  }
} {1 0 0 1 0 0 0}
do_test null-2.8 {
  execsql {
    select ifnull(case c when b then 1 else 0 end, 99) from t1;
  }
} {1 0 0 1 0 0 0}

# Check to see that NULL values are ignored in aggregate functions.
#
do_test null-3.1 {
  execsql {
    select count(*), count(b), count(c), sum(b), sum(c), 
           avg(b), avg(c), min(b), max(b) from t1;
  }
} {7 4 6 2 3 0.5 0.5 0 1}

# Check to see how WHERE clauses handle NULL values.  A NULL value
# is the same as UNKNOWN.  The WHERE clause should only select those
# rows that are TRUE.  FALSE and UNKNOWN rows are rejected.
#
do_test null-4.1 {
  execsql {
    select a from t1 where b<10
  }
} {1 2 3 4}
do_test null-4.2 {
  execsql {
    select a from t1 where not b>10
  }
} {1 2 3 4}
do_test null-4.3 {
  execsql {
    select a from t1 where b<10 or c=1;
  }
} {1 2 3 4 6}
do_test null-4.4 {
  execsql {
    select a from t1 where b<10 and c=1;
  }
} {2 4}
do_test null-4.5 {
  execsql {
    select a from t1 where not (b<10 and c=1);
  }
} {1 3 5}

# The DISTINCT keyword on a SELECT statement should treat NULL values
# as distinct
#
do_test null-5.1 {
  execsql {
    select distinct b from t1 order by b;
  }
} {{} 0 1}

# A UNION to two queries should treat NULL values
# as distinct
#
do_test null-6.1 {
  execsql {
    select b from t1 union select c from t1 order by c;
  }
} {{} 0 1}

# The UNIQUE constraint only applies to non-null values
#
do_test null-7.1 {
  execsql {
    create table t2(a, b unique on conflict ignore);
    insert into t2 values(1,1);
    insert into t2 values(2,null);
    insert into t2 values(3,null);
    insert into t2 values(4,1);
    select a from t2;
  }
} {1 2 3}
do_test null-7.2 {
  execsql {
    create table t3(a, b, c, unique(b,c) on conflict ignore);
    insert into t3 values(1,1,1);
    insert into t3 values(2,null,1);
    insert into t3 values(3,null,1);
    insert into t3 values(4,1,1);
    select a from t3;
  }
} {1 2 3}



finish_test

#    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 UNION, INTERSECT and EXCEPT operators
# in SELECT statements.
#
# $Id: select4.test,v 1.9 2002/05/31 15:51:26 drh Exp $

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

# Build some test data
#
set fd [open data1.txt w]

    SELECT log, count(*) FROM t1 GROUP BY log
    UNION
    SELECT log, n FROM t1 WHERE n=7
    ORDER BY count(*), log;
  }
} {0 1 1 1 2 2 3 4 3 7 4 8 5 15}

# NULLs are indistinct for the UNION operator.
# Make sure the UNION operator recognizes this
#
do_test select4-6.3 {
  execsql {
    SELECT NULL UNION SELECT NULL UNION
    SELECT 1 UNION SELECT 2 AS 'x'
    ORDER BY x;
  }
} {{} 1 2}
do_test select4-6.3.1 {
  execsql {
    SELECT NULL UNION ALL SELECT NULL UNION ALL
    SELECT 1 UNION ALL SELECT 2 AS 'x'
    ORDER BY x;
  }
} {{} {} 1 2}

# Make sure the DISTINCT keyword treats NULLs as indistinct.
#
do_test select4-6.4 {
  execsql {
    SELECT * FROM (
       SELECT NULL, 1 UNION ALL SELECT NULL, 1
    );
  }
} {{} 1 {} 1}
do_test select4-6.5 {
  execsql {
    SELECT DISTINCT * FROM (
       SELECT NULL, 1 UNION ALL SELECT NULL, 1
    );
  }
} {{} 1}
do_test select4-6.6 {
  execsql {
    SELECT DISTINCT * FROM (
       SELECT 1,2  UNION ALL SELECT 1,2
    );
  }
} {1 2}

# Test distinctness of NULL in other ways.
#
do_test select4-6.7 {
  execsql {
    SELECT NULL EXCEPT SELECT NULL
  }
} {}


# Make sure column names are correct when a compound select appears as
# an expression in the WHERE clause.
#
do_test select4-7.1 {
  execsql {