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Overview
Comment:Fix comments on the implementation of the SUM() function. (CVS 3183)
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SHA1: a8909f3e5fc67ac1ba7d1abd7fb0f4004fec5984
User & Date: drh 2006-05-11 13:25:39.000
Context
2006-05-11
13:26
Correctly handle multi-column indices where multiple columns are constrained by IN operators with subqueries on the right-hand side. Ticket #1807. (CVS 3184) (check-in: b16541ba5e user: drh tags: trunk)
13:25
Fix comments on the implementation of the SUM() function. (CVS 3183) (check-in: a8909f3e5f user: drh tags: trunk)
2006-05-10
14:39
Out-of-memory checks added to tclsqlite.c and shell.c. Tickets #1805 and #1806. (CVS 3182) (check-in: 364031d6e5 user: drh tags: trunk)
Changes
Unified Diff Ignore Whitespace Patch
Changes to src/func.c.
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** 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 1.127 2006/04/07 13:26:43 drh Exp $
*/
#include "sqliteInt.h"
#include <ctype.h>
/* #include <math.h> */
#include <stdlib.h>
#include <assert.h>
#include "vdbeInt.h"








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** 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 1.128 2006/05/11 13:25:39 drh Exp $
*/
#include "sqliteInt.h"
#include <ctype.h>
/* #include <math.h> */
#include <stdlib.h>
#include <assert.h>
#include "vdbeInt.h"
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/*
** Routines used to compute the sum, average, and total.
**
** The SUM() function follows the (broken) SQL standard which means
** that it returns NULL if it sums over no inputs.  TOTAL returns
** 0.0 in that case.  In addition, TOTAL always returns a float where
** SUM might return an integer if it never encounters a floating point
** value.
**
** I am told that SUM() should raise an exception if it encounters
** a integer overflow.  But after pondering this, I decided that 
** behavior leads to brittle programs.  So instead, I have coded
** SUM() to revert to using floating point if it encounters an
** integer overflow.  The answer may not be exact, but it will be
** close.  If the SUM() function returns an integer, the value is
** exact.  If SUM() returns a floating point value, it means the
** value might be approximated.
*/
static void sumStep(sqlite3_context *context, int argc, sqlite3_value **argv){
  SumCtx *p;
  int type;
  assert( argc==1 );
  p = sqlite3_aggregate_context(context, sizeof(*p));
  type = sqlite3_value_numeric_type(argv[0]);








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/*
** Routines used to compute the sum, average, and total.
**
** The SUM() function follows the (broken) SQL standard which means
** that it returns NULL if it sums over no inputs.  TOTAL returns
** 0.0 in that case.  In addition, TOTAL always returns a float where
** SUM might return an integer if it never encounters a floating point
** value.  TOTAL never fails, but SUM might through an exception if






** it overflows an integer.


*/
static void sumStep(sqlite3_context *context, int argc, sqlite3_value **argv){
  SumCtx *p;
  int type;
  assert( argc==1 );
  p = sqlite3_aggregate_context(context, sizeof(*p));
  type = sqlite3_value_numeric_type(argv[0]);
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