NULLs compare equal to each other when computing GROUP BY categories. (CVS 2728)

FossilOrigin-Name: d9b0c9705379a8b3a28a83bb29fc1cd688fe184e

manifest

@@ -1,5 +1,5 @@
-C Update\scomments\sin\swhere.c.\s\sNo\scode\schanges.\s(CVS\s2727)
-D 2005-09-20T08:47:20
+C NULLs\scompare\sequal\sto\seach\sother\swhen\scomputing\sGROUP\sBY\scategories.\s(CVS\s2728)
+D 2005-09-20T13:12:00
 F Makefile.in 12784cdce5ffc8dfb707300c34e4f1eb3b8a14f1
 F Makefile.linux-gcc 06be33b2a9ad4f005a5f42b22c4a19dab3cbb5c7
 F README 9c4e2d6706bdcc3efdd773ce752a8cdab4f90028
@@ -63,7 +63,7 @@ F src/pragma.c 6d773e25e8af13ef0820531ad2793417f8a8959d
 F src/prepare.c fc098db25d2a121affb08686cf04833fd50452d4
 F src/printf.c bd421c1ad5e01013c89af63c60eab02852ccd15e
 F src/random.c 90adff4e73a3b249eb4f1fc2a6ff9cf78c7233a4
-F src/select.c c3fe1994da81df0e09c4604ef75180f249cabe10
+F src/select.c 52b72b7fe11ce4ddc136074a1b48ea69453f60fd
 F src/shell.c 3596c1e559b82663057940d19ba533ad421c7dd3
 F src/sqlite.h.in 461b2535550cf77aedfd44385da11ef7d63e57a2
 F src/sqliteInt.h 53daa72541b4336c5e89773cf39717ed695bd523
@@ -80,7 +80,7 @@ F src/update.c c2716c2115533ffae3d08bf8853aaba4f970f37e
 F src/utf.c bda5eb85039ef16f2d17004c1e18c96e1ab0a80c
 F src/util.c 55caaffbb2716f9928ab452d20f3e9cbbeab872d
 F src/vacuum.c 829d9e1a6d7c094b80e0899686670932eafd768c
-F src/vdbe.c de007d59f036fcd1b89a7d4172aa0d028e8689eb
+F src/vdbe.c 2a5c9474c9538e18347ab63988bad4e3de074403
 F src/vdbe.h c8e105979fc7aaf5b8004e9621904e3bd096dfa2
 F src/vdbeInt.h 7bedbb9553a10e86b53f75d99e197f3f00a732bf
 F src/vdbeapi.c 85bbe1d0243a89655433d60711b4bd71979b59cd
@@ -203,7 +203,7 @@ F test/select1.test 480233d4f5a81d7d59a55e40d05084d97e57ecdf
 F test/select2.test f3c2678c3a9f3cf08ec4988a3845bda64be6d9e3
 F test/select3.test 576df1a5cc5e01dadae9176384e2d506315afdcf
 F test/select4.test c239f516aa31f42f2ef7c6d7cd01105f08f934ca
-F test/select5.test cf5c42137d915b5e866c99d018be67dad9ebed75
+F test/select5.test 93323dd60ea8dfe2c5fee86644279dee5ad5ea23
 F test/select6.test 21b72c56e7cbcefd063fdf9bc6c89342aedabccf
 F test/select7.test 1bf795b948c133a15a2a5e99d3270e652ec58ce6
 F test/sort.test 0c33a8ae1c238377ad197387c3872175f40d3843
@@ -311,7 +311,7 @@ F www/tclsqlite.tcl ddcf912ea48695603c8ed7efb29f0812ef8d1b49
 F www/vdbe.tcl 87a31ace769f20d3627a64fa1fade7fed47b90d0
 F www/version3.tcl a99cf5f6d8bd4d5537584a2b342f0fb9fa601d8b
 F www/whentouse.tcl 97e2b5cd296f7d8057e11f44427dea8a4c2db513
-P 6ec8883c366532948e619830ff7d9f63b79fc08b
-R 83e2318d245416067a9bf94d66214656
+P bb84d27eda64479d65b13fbbcaeef6a00da4d103
+R ec917b8e5b94d2118eb0bbfbe6d750c0
 U drh
-Z 7b8f65438258711df695628d2834385c
+Z 353c0c657af079f4a5983ad6b31ab9ff

manifest.uuid

@@ -1 +1 @@
-bb84d27eda64479d65b13fbbcaeef6a00da4d103
+d9b0c9705379a8b3a28a83bb29fc1cd688fe184e

src/select.c

@@ -12,7 +12,7 @@
 ** This file contains C code routines that are called by the parser
 ** to handle SELECT statements in SQLite.
 **
-** $Id: select.c,v 1.272 2005/09/19 21:05:49 drh Exp $
+** $Id: select.c,v 1.273 2005/09/20 13:12:00 drh Exp $
 */
 #include "sqliteInt.h"
 
@@ -2852,6 +2852,7 @@ int sqlite3Select(
     int addrProcessRow;     /* Code to process a single input row */
     int addrEnd;            /* End of all processing */
     int addrSortingIdx;     /* The OP_OpenVirtual for the sorting index */
+    int addrReset;          /* Subroutine for resetting the accumulator */
 
     addrEnd = sqlite3VdbeMakeLabel(v);
 
@@ -2947,12 +2948,19 @@ int sqlite3Select(
       }
       sqlite3VdbeAddOp(v, OP_Return, 0, 0);
 
+      /* Generate a subroutine that will reset the group-by accumulator
+      */
+      addrReset = sqlite3VdbeCurrentAddr(v);
+      resetAccumulator(pParse, &sAggInfo);
+      sqlite3VdbeAddOp(v, OP_Return, 0, 0);
+
       /* Begin a loop that will extract all source rows in GROUP BY order.
       ** This might involve two separate loops with an OP_Sort in between, or
       ** it might be a single loop that uses an index to extract information
       ** in the right order to begin with.
       */
       sqlite3VdbeResolveLabel(v, addrInitializeLoop);
+      sqlite3VdbeAddOp(v, OP_Gosub, 0, addrReset);
       pWInfo = sqlite3WhereBegin(pParse, pTabList, pWhere, &pGroupBy);
       if( pWInfo==0 ) goto select_end;
       if( pGroupBy==0 ){
@@ -3010,9 +3018,9 @@ int sqlite3Select(
         }
         sqlite3VdbeAddOp(v, OP_MemLoad, iAMem+j, 0);
         if( j==0 ){
-          sqlite3VdbeAddOp(v, OP_Eq, 0, addrProcessRow);
+          sqlite3VdbeAddOp(v, OP_Eq, 0x200, addrProcessRow);
         }else{
-          sqlite3VdbeAddOp(v, OP_Ne, 0x100, addrGroupByChange);
+          sqlite3VdbeAddOp(v, OP_Ne, 0x300, addrGroupByChange);
         }
         sqlite3VdbeChangeP3(v, -1, (void*)pKeyInfo->aColl[j], P3_COLLSEQ);
       }
@@ -3033,7 +3041,7 @@ int sqlite3Select(
       }
       sqlite3VdbeAddOp(v, OP_Gosub, 0, addrOutputRow);
       sqlite3VdbeAddOp(v, OP_IfMemPos, iAbortFlag, addrEnd);
-      resetAccumulator(pParse, &sAggInfo);
+      sqlite3VdbeAddOp(v, OP_Gosub, 0, addrReset);
 
       /* Update the aggregate accumulators based on the content of
       ** the current row

src/vdbe.c

@@ -43,7 +43,7 @@
 ** in this file for details.  If in doubt, do not deviate from existing
 ** commenting and indentation practices when changing or adding code.
 **
-** $Id: vdbe.c,v 1.488 2005/09/17 15:20:28 drh Exp $
+** $Id: vdbe.c,v 1.489 2005/09/20 13:12:00 drh Exp $
 */
 #include "sqliteInt.h"
 #include "os.h"
@@ -1411,8 +1411,9 @@ case OP_ToBlob: {                  /* no-push */
 ** jump to instruction P2.  Otherwise, continue to the next instruction.
 **
 ** If the 0x100 bit of P1 is true and either operand is NULL then take the
-** jump.  If the 0x100 bit of P1 is false then fall thru if either operand
-** is NULL.
+** jump.  If the 0x100 bit of P1 is clear then fall thru if either operand
+** is NULL.  If the 0x200 bit of P1 is set and both operands are NULL, then
+** return true or take the jump - treat NULL values as just another number.
 **
 ** The least significant byte of P1 (mask 0xff) must be an affinity character -
 ** 'n', 't', 'i' or 'o' - or 0x00. An attempt is made to coerce both values
@@ -1481,14 +1482,29 @@ case OP_Ge: {             /* same as TK_GE, no-push */
   ** the stack.
   */
   if( flags&MEM_Null ){
-    popStack(&pTos, 2);
-    if( pOp->p2 ){
-      if( pOp->p1 & 0x100 ) pc = pOp->p2-1;
+    if( (pOp->p1 & 0x200)!=0 && (pTos->flags & pNos->flags & MEM_Null)!=0 ){
+      /* If the 0x200 bit of P1 is set and *both* operands are NULL, then
+      ** pretend that both operands are integer 0.  This will cause the the
+      ** various comparison operators to threat NULL just like any other value.
+      */
+      pTos->flags = pNos->flags = MEM_Int;
+      pTos->i = pNos->i = 0;
     }else{
-      pTos++;
-      pTos->flags = MEM_Null;
+      /* If the 0x200 bit of P1 is clear or only one of the operands is NULL,
+      ** then the result is always NULL.  The jump is taken if the 0x100 bit
+      ** of P1 is set.
+      */
+      popStack(&pTos, 2);
+      if( pOp->p2 ){
+        if( pOp->p1 & 0x100 ){
+          pc = pOp->p2-1;
+        }
+      }else{
+        pTos++;
+        pTos->flags = MEM_Null;
+      }
+      break;
     }
-    break;
   }
 
   affinity = pOp->p1 & 0xFF;

test/select5.test

@@ -12,7 +12,7 @@
 # focus of this file is testing aggregate functions and the
 # GROUP BY and HAVING clauses of SELECT statements.
 #
-# $Id: select5.test,v 1.13 2005/09/08 20:37:44 drh Exp $
+# $Id: select5.test,v 1.14 2005/09/20 13:12:00 drh Exp $
 
 set testdir [file dirname $argv0]
 source $testdir/tester.tcl
@@ -156,4 +156,17 @@ do_test select5-5.5 {
   } 
 } {1 4 6 4}
 
+# NULL compare equal to each other for the purposes of processing
+# the GROUP BY clause.
+#
+do_test select5-6.1 {
+  execsql {
+    CREATE TABLE t3(x,y);
+    INSERT INTO t3 VALUES(1,NULL);
+    INSERT INTO t3 VALUES(2,NULL);
+    INSERT INTO t3 VALUES(3,4);
+    SELECT count(x), y FROM t3 GROUP BY y ORDER BY 1
+  }
+} {1 4 2 {}}
+  
 finish_test