Better resolution of ORDER BY terms in compound queries. Candidate

solution for ticket #2822.  Needs more testing and documentation
before going final. (CVS 4602)

FossilOrigin-Name: 62a78d212c53a9cb1759d03134653a75f3a086b6

manifest

@@ -1,5 +1,5 @@
-C Strengthen\sthe\stests\sfor\saggregate\sfunctions\sin\sGROUP\sBY\sclauses.\nChanges\sto\stest\scases\sonly.\s\sNo\schanges\sto\scode.\s(CVS\s4601)
+C Better\sresolution\sof\sORDER\sBY\sterms\sin\scompound\squeries.\s\sCandidate\nsolution\sfor\sticket\s#2822.\s\sNeeds\smore\stesting\sand\sdocumentation\nbefore\sgoing\sfinal.\s(CVS\s4602)
-D 2007-12-08T18:01:31
+D 2007-12-08T21:10:20
 F Makefile.arm-wince-mingw32ce-gcc ac5f7b2cef0cd850d6f755ba6ee4ab961b1fadf7
 F Makefile.in 30789bf70614bad659351660d76b8e533f3340e9
 F Makefile.linux-gcc d53183f4aa6a9192d249731c90dbdffbd2c68654
@@ -131,7 +131,7 @@ F src/pragma.c 0246032dbe681dded8710ac43eaf654eead1434e
 F src/prepare.c f811fdb6fd4a82cca673a6e1d5b041d6caf567f1
 F src/printf.c c94a2571a828b927c64f5e3ed3584da8a91fcaec
 F src/random.c 4a22746501bf36b0a088c66e38dde5daba6a35da
-F src/select.c 7c0ab94b8f287eb94fdb1eb101be603832ecfc34
+F src/select.c 2c08239b55cf93c03a79cbdedf1ac89967fd6acb
 F src/server.c 087b92a39d883e3fa113cae259d64e4c7438bc96
 F src/shell.c c97be281cfc3dcb14902f45e4b16f20038eb83ff
 F src/sqlite.h.in 544587c10005dde0ad8f132dd9b7816b132b2bea
@@ -411,10 +411,10 @@ F test/rowid.test d125991eea1ffdea800d48471afd8fc4acc10b01
 F test/safety.test 4a06934e45d03b8b50ebcd8d174eb0367d2fd851
 F test/schema.test a8b000723375fd42c68d310091bdbd744fde647c
 F test/schema2.test 35e1c9696443d6694c8980c411497c2b5190d32e
-F test/select1.test 7603a4d406ea00516233e26539d2fac0cc85e732
+F test/select1.test d091e1c8ad23c9bd6d7d55d2dd16b08e68e16f63
 F test/select2.test f3c2678c3a9f3cf08ec4988a3845bda64be6d9e3
 F test/select3.test 47439f28862489626b483b0c718cfb0562e6f6d5
-F test/select4.test 305ba0a6e97efc5544def5e5cb49b54e1bf87fd9
+F test/select4.test 4192e6c712194d53b4b77f094eb9d880b8d5ac0e
 F test/select5.test 0b47058d3e916c1fc9fe81f44b438e02bade21ce
 F test/select6.test 399f14b9ba37b768afe5d2cd8c12e4f340a69db8
 F test/select7.test 7906735805cfbee4dddc0bed4c14e68d7f5f9c5f
@@ -597,7 +597,7 @@ F www/tclsqlite.tcl 8be95ee6dba05eabcd27a9d91331c803f2ce2130
 F www/vdbe.tcl 87a31ace769f20d3627a64fa1fade7fed47b90d0
 F www/version3.tcl 890248cf7b70e60c383b0e84d77d5132b3ead42b
 F www/whentouse.tcl fc46eae081251c3c181bd79c5faef8195d7991a5
-P 1d6a9f5fafb862fb31c8589fa118a5672bad6abd
+P 4be8e6765bf8bc48747b2542f2ed77066fb9dcb9
-R 378bf8f52e8d83775a501365b0bea297
+R adfe92f0c9624e9b76a7c1a73370b4bd
 U drh
-Z 0788daae7a5c65291d88fcc1de49b7ff
+Z af9ac541bec9448e79940f97cacc1ce8

manifest.uuid

@@ -1 +1 @@
-4be8e6765bf8bc48747b2542f2ed77066fb9dcb9
+62a78d212c53a9cb1759d03134653a75f3a086b6

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 1.363 2007/11/23 13:42:52 drh Exp $
+** $Id: select.c,v 1.364 2007/12/08 21:10:20 drh Exp $
 */
 #include "sqliteInt.h"
 
@@ -1412,6 +1412,15 @@ static int prepSelectStmt(Parse *pParse, Select *p){
   return rc;
 }
 
+/*
+** During the process of matching ORDER BY terms to columns of the 
+** result set, the Exprlist.a[].done flag can be set to one of the
+** following values:
+*/
+#define ORDERBY_MATCH_NONE     0   /* No match found */
+#define ORDERBY_MATCH_PARTIAL  1   /* A good match, but not perfect */
+#define ORDERBY_MATCH_EXACT    2   /* An exact match seen */
+
 #ifndef SQLITE_OMIT_COMPOUND_SELECT
 /*
 ** This routine associates entries in an ORDER BY expression list with
@@ -1431,33 +1440,43 @@ static int matchOrderbyToColumn(
   Select *pSelect,        /* Match to result columns of this SELECT */
   ExprList *pOrderBy,     /* The ORDER BY values to match against columns */
   int iTable,             /* Insert this value in iTable */
-  int mustComplete        /* If TRUE all ORDER BYs must match */
+  int rightMost           /* TRUE for outermost recursive invocation */
 ){
   int nErr = 0;
   int i, j;
   ExprList *pEList;
   sqlite3 *db = pParse->db;
+  NameContext nc;
 
   if( pSelect==0 || pOrderBy==0 ) return 1;
-  if( mustComplete ){
+  if( rightMost ){
-    for(i=0; i<pOrderBy->nExpr; i++){ pOrderBy->a[i].done = 0; }
+    assert( pSelect->pOrderBy==pOrderBy );
-  }
-  if( prepSelectStmt(pParse, pSelect) ){
-    return 1;
-  }
-  if( pSelect->pPrior ){
-    if( matchOrderbyToColumn(pParse, pSelect->pPrior, pOrderBy, iTable, 0) ){
-      return 1;
-    }
-  }
-  pEList = pSelect->pEList;
     for(i=0; i<pOrderBy->nExpr; i++){
+      pOrderBy->a[i].done = ORDERBY_MATCH_NONE;
+    }
+  }
+  if( pSelect->pPrior
+      && matchOrderbyToColumn(pParse, pSelect->pPrior, pOrderBy, iTable, 0) ){
+    return 1;
+  }
+  if( sqlite3SelectResolve(pParse, pSelect, 0) ){
+    return 1;
+  }
+  memset(&nc, 0, sizeof(nc));
+  nc.pParse = pParse;
+  nc.pSrcList = pSelect->pSrc;
+  nc.pEList = pEList = pSelect->pEList;
+  nc.allowAgg = 1;
+  for(i=0; nErr==0 && i<pOrderBy->nExpr; i++){
     struct ExprList_item *pItem;
     Expr *pE = pOrderBy->a[i].pExpr;
     int iCol = -1;
-    char *zLabel;
+    int match = ORDERBY_MATCH_NONE;
+    Expr *pDup;
 
-    if( pOrderBy->a[i].done ) continue;
+    if( pOrderBy->a[i].done==ORDERBY_MATCH_EXACT ){
+      continue;
+    }
     if( sqlite3ExprIsInteger(pE, &iCol) ){
       if( iCol<=0 || iCol>pEList->nExpr ){
         sqlite3ErrorMsg(pParse,
@@ -1466,34 +1485,38 @@ static int matchOrderbyToColumn(
         nErr++;
         break;
       }
-      if( !mustComplete ) continue;
+      if( !rightMost ) continue;
       iCol--;
+      match = ORDERBY_MATCH_EXACT;
     }
-    if( iCol<0 && (zLabel = sqlite3NameFromToken(db, &pE->token))!=0 ){
+    if( !match && pParse->nErr==0 && (pDup = sqlite3ExprDup(db, pE))!=0 ){
-      for(j=0, pItem=pEList->a; j<pEList->nExpr; j++, pItem++){
+      nc.nErr = 0;
-        char *zName;
+      assert( pParse->zErrMsg==0 );
-        int isMatch;
+      if( sqlite3ExprResolveNames(&nc, pDup) ){
-        if( pItem->zName ){
+        sqlite3ErrorClear(pParse);
-          zName = sqlite3DbStrDup(db, pItem->zName);
       }else{
-          zName = sqlite3NameFromToken(db, &pItem->pExpr->token);
+        for(j=0, pItem=pEList->a; j<pEList->nExpr; j++, pItem++){
-        }
+          if( sqlite3ExprCompare(pItem->pExpr, pDup) ){
-        isMatch = zName && sqlite3StrICmp(zName, zLabel)==0;
-        sqlite3_free(zName);
-        if( isMatch ){
             iCol = j;
+            match = ORDERBY_MATCH_PARTIAL;
             break;
           }
         }
-      sqlite3_free(zLabel);
       }
-    if( iCol>=0 ){
+      sqlite3ExprDelete(pDup);
+    }
+    if( match ){
       pE->op = TK_COLUMN;
-      pE->iColumn = iCol;
       pE->iTable = iTable;
       pE->iAgg = -1;
-      pOrderBy->a[i].done = 1;
+      if( pOrderBy->a[i].done!=ORDERBY_MATCH_NONE && pE->iColumn!=iCol ){
-    }else if( mustComplete ){
+        sqlite3ErrorMsg(pParse,
+          "ORDER BY term number %d is ambiguous", i+1);
+        nErr++;
+      }
+      pE->iColumn = iCol;
+      pOrderBy->a[i].done = match;
+    }else if( rightMost && pOrderBy->a[i].done==ORDERBY_MATCH_NONE ){
       sqlite3ErrorMsg(pParse,
         "ORDER BY term number %d does not match any result column", i+1);
       nErr++;
@@ -2720,11 +2743,11 @@ int sqlite3SelectResolve(
      sqlite3ExprResolveNames(&sNC, p->pHaving) ){
     return SQLITE_ERROR;
   }
-  if( p->pPrior==0 ){
+  if( p->pPrior==0 && processOrderGroupBy(&sNC, p->pOrderBy, "ORDER") ){
-    if( processOrderGroupBy(&sNC, p->pOrderBy, "ORDER") ||
-        processOrderGroupBy(&sNC, pGroupBy, "GROUP") ){
     return SQLITE_ERROR;
   }
+  if( processOrderGroupBy(&sNC, pGroupBy, "GROUP") ){
+    return SQLITE_ERROR;
   }
 
   if( pParse->db->mallocFailed ){

test/select1.test

@@ -11,7 +11,7 @@
 # This file implements regression tests for SQLite library.  The
 # focus of this file is testing the SELECT statement.
 #
-# $Id: select1.test,v 1.54 2007/07/23 22:51:15 drh Exp $
+# $Id: select1.test,v 1.55 2007/12/08 21:10:20 drh Exp $
 
 set testdir [file dirname $argv0]
 source $testdir/tester.tcl
@@ -517,7 +517,7 @@ do_test select1-6.10 {
 do_test select1-6.11 {
   set v [catch {execsql2 {
     SELECT f1 FROM test1 UNION SELECT f2+100 FROM test1
-    ORDER BY f2+100;
+    ORDER BY f2+101;
   }} msg]
   lappend v $msg
 } {1 {ORDER BY term number 1 does not match any result column}}

test/select4.test

@@ -12,7 +12,7 @@
 # focus of this file is testing UNION, INTERSECT and EXCEPT operators
 # in SELECT statements.
 #
-# $Id: select4.test,v 1.20 2006/06/20 11:01:09 danielk1977 Exp $
+# $Id: select4.test,v 1.21 2007/12/08 21:10:20 drh Exp $
 
 set testdir [file dirname $argv0]
 source $testdir/tester.tcl
@@ -283,7 +283,7 @@ do_test select4-5.2b {
     SELECT DISTINCT log AS xyzzy FROM t1
     UNION ALL
     SELECT n FROM t1 WHERE log=3
-    ORDER BY 'xyzzy';
+    ORDER BY "xyzzy";
   }} msg]
   lappend v $msg
 } {0 {0 1 2 3 4 5 5 6 7 8}}
@@ -292,7 +292,7 @@ do_test select4-5.2c {
     SELECT DISTINCT log FROM t1
     UNION ALL
     SELECT n FROM t1 WHERE log=3
-    ORDER BY 'xyzzy';
+    ORDER BY "xyzzy";
   }} msg]
   lappend v $msg
 } {1 {ORDER BY term number 1 does not match any result column}}
@@ -301,7 +301,7 @@ do_test select4-5.2d {
     SELECT DISTINCT log FROM t1
     INTERSECT
     SELECT n FROM t1 WHERE log=3
-    ORDER BY 'xyzzy';
+    ORDER BY "xyzzy";
   }} msg]
   lappend v $msg
 } {1 {ORDER BY term number 1 does not match any result column}}