Make sure group_concat() ignores initial NULL values. (CVS 6787)

FossilOrigin-Name: 90c3b23ccac8a9e7fc1cc831e43888e4e43badc9

manifest

@@ -1,5 +1,5 @@
-C Reorganize\sand\scleanup\sthe\sprepared\sstatement\sobject.\s\sRemove\scode\sthat\shas\nbeen\scommented\sout\sfor\sages\sand\sis\sno\slonger\srelevant\sto\sanything.\s(CVS\s6786)
-D 2009-06-19T14:06:03
+C Make\ssure\sgroup_concat()\signores\sinitial\sNULL\svalues.\s(CVS\s6787)
+D 2009-06-19T16:44:41
 F Makefile.arm-wince-mingw32ce-gcc fcd5e9cd67fe88836360bb4f9ef4cb7f8e2fb5a0
 F Makefile.in 8b8fb7823264331210cddf103831816c286ba446
 F Makefile.linux-gcc d53183f4aa6a9192d249731c90dbdffbd2c68654
@@ -116,7 +116,7 @@ F src/date.c ab5f7137656652a48434d64f96bdcdc823bb23b3
 F src/delete.c cb791855c7948cecc96def9d97989879ca26f257
 F src/expr.c 1d580a7b2e51092785cbbc1fb8d2ff84e93c76dc
 F src/fault.c dc88c821842157460750d2d61a8a8b4197d047ff
-F src/func.c d108b0028050ecd0fd9508268995892937d577ae
+F src/func.c 9856373f5315f6b8690d7f07f7191aa9f279ca87
 F src/global.c 448419c44ce0701104c2121b0e06919b44514c0c
 F src/hash.c ebcaa921ffd9d86f7ea5ae16a0a29d1c871130a7
 F src/hash.h 35b216c13343d0b4f87d9f21969ac55ad72174e1
@@ -384,7 +384,7 @@ F test/fts3e.test 1f6c6ac9cc8b772ca256e6b22aaeed50c9350851
 F test/fts3expr.test 9764961c3f4ac818dacda01ed35d8bfcef42338b
 F test/fts3expr2.test 18da930352e5693eaa163a3eacf96233b7290d1a
 F test/fts3near.test dc196dd17b4606f440c580d45b3d23aa975fd077
-F test/func.test d4a8590511cdc68a136afd00bd989c2584454932
+F test/func.test 004caa157b91986bed8c85d7c7d0a86d6e10528d
 F test/fuzz.test a4174c3009a3e2c2e14b31b364ebf7ddb49de2c9
 F test/fuzz2.test ea38692ce2da99ad79fe0be5eb1a452c1c4d37bb
 F test/fuzz3.test aec64345184d1662bd30e6a17851ff659d596dc5
@@ -736,7 +736,7 @@ F tool/speedtest2.tcl ee2149167303ba8e95af97873c575c3e0fab58ff
 F tool/speedtest8.c 2902c46588c40b55661e471d7a86e4dd71a18224
 F tool/speedtest8inst1.c 293327bc76823f473684d589a8160bde1f52c14e
 F tool/vdbe-compress.tcl 672f81d693a03f80f5ae60bfefacd8a349e76746
-P 7d8f178c8145b90da31f6557f7cd99d154eb676e
-R b3e036533bac5a29d77c23602f39da64
+P 37ae5f5e8feb34a8e6e8b34aa18df1e9a1ce55cb
+R bbe11c7b362a2c517acbc2d78fa4631d
 U drh
-Z f2670ca2615f8f31d0717b2c5d58ef64
+Z 1470050dd5090450f94c26db6cf0c170

manifest.uuid

@@ -1 +1 @@
-37ae5f5e8feb34a8e6e8b34aa18df1e9a1ce55cb
+90c3b23ccac8a9e7fc1cc831e43888e4e43badc9

src/func.c

@@ -16,7 +16,7 @@
 ** sqliteRegisterBuildinFunctions() found at the bottom of the file.
 ** All other code has file scope.
 **
-** $Id: func.c,v 1.238 2009/06/19 14:06:03 drh Exp $
+** $Id: func.c,v 1.239 2009/06/19 16:44:41 drh Exp $
 */
 #include "sqliteInt.h"
 #include <stdlib.h>
@@ -1265,15 +1265,10 @@ static void groupConcatStep(
 
   if( pAccum ){
     sqlite3 *db = sqlite3_context_db_handle(context);
-    int n;
+    int firstTerm = pAccum->useMalloc==0;
     pAccum->useMalloc = 1;
     pAccum->mxAlloc = db->aLimit[SQLITE_LIMIT_LENGTH];
-#ifdef SQLITE_OMIT_DEPRECATED
-    n = context->pMem->n;
-#else
-    n = sqlite3_aggregate_count(context);
-#endif
-    if( n>1 ){
+    if( !firstTerm ){
       if( argc==2 ){
         zSep = (char*)sqlite3_value_text(argv[1]);
         nSep = sqlite3_value_bytes(argv[1]);

test/func.test

@@ -11,7 +11,7 @@
 # This file implements regression tests for SQLite library.  The
 # focus of this file is testing built-in functions.
 #
-# $Id: func.test,v 1.92 2009/04/15 15:16:53 drh Exp $
+# $Id: func.test,v 1.93 2009/06/19 16:44:41 drh Exp $
 
 set testdir [file dirname $argv0]
 source $testdir/tester.tcl
@@ -1057,7 +1057,7 @@ for {set i 1} {$i<[sqlite3_limit db SQLITE_LIMIT_FUNCTION_ARG -1]} {incr i} {
 }
 
 # Ticket #3806.  If the initial string in a group_concat is an empty
-# string, the separate that follows should still be present.
+# string, the separator that follows should still be present.
 #
 do_test func-24.8 {
   execsql {
@@ -1070,6 +1070,27 @@ do_test func-24.9 {
   }
 } {,,,,software}
 
+# Ticket #3923.  Initial empty strings have a separator.  But initial
+# NULLs do not.
+#
+do_test func-24.10 {
+  execsql {
+    SELECT group_concat(CASE t1 WHEN 'this' THEN null ELSE t1 END) FROM tbl1
+  }
+} {program,is,free,software}
+do_test func-24.11 {
+  execsql {
+   SELECT group_concat(CASE WHEN t1!='software' THEN null ELSE t1 END) FROM tbl1
+  }
+} {software}
+do_test func-24.12 {
+  execsql {
+    SELECT group_concat(CASE t1 WHEN 'this' THEN ''
+                          WHEN 'program' THEN null ELSE t1 END) FROM tbl1
+  }
+} {,is,free,software}
+
+
 # Use the test_isolation function to make sure that type conversions
 # on function arguments do not effect subsequent arguments.
 #