ORDER BY in a compound SELECT will first match against the left-most SELECT.

If there is no match there, it begins working its way to the right. (CVS 4621)

FossilOrigin-Name: 56063ec84b130bcdb0e90bc76fabca394d0d867f

test/null.test

@@ -150,7 +150,13 @@ do_test null-5.1 {
 } {{} 0 1}
 
 # A UNION to two queries should treat NULL values
-# as distinct
+# as distinct.
+#
+# (Later:)  We also take this opportunity to test the ability
+# of an ORDER BY clause to bind to either SELECT of a UNION.
+# The left-most SELECT is preferred.  In standard SQL, only
+# the left SELECT can be used.  The ability to match an ORDER
+# BY term to the right SELECT is an SQLite extension.
 #
 ifcapable compound {
   do_test null-6.1 {
@@ -173,6 +179,16 @@ ifcapable compound {
       select b from t1 union select c from t1 order by main.t1.b;
     }
   } {{} 0 1}
+  do_test null-6.5 {
+    execsql {
+      select b from t1 union select c from t1 order by t1.a;
+    }
+  } {{} 0 1}
+  do_test null-6.6 {
+    execsql {
+      select b from t1 union select c from t1 order by main.t1.a;
+    }
+  } {{} 0 1}
 } ;# ifcapable compound
 
 # The UNIQUE constraint only applies to non-null values

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 1.22 2007/12/10 18:51:48 danielk1977 Exp $
+# $Id: select4.test,v 1.23 2007/12/13 03:45:08 drh Exp $
 
 set testdir [file dirname $argv0]
 source $testdir/tester.tcl
@@ -210,12 +210,15 @@ do_test select4-4.1.1 {
 
 do_test select4-4.1.2 {
   execsql {
-    SELECT DISTINCT log FROM t1 UNION ALL SELECT 6
+    SELECT DISTINCT log FROM t1
+    UNION ALL
+    SELECT 6
     INTERSECT
     SELECT n FROM t1 WHERE log=3
-    ORDER BY log;
+    ORDER BY t1.log;
   }
 } {5 6}
+
 do_test select4-4.1.3 {
   execsql {
     CREATE TABLE t2 AS