Automerge.

mysql-test/r/olap.result

@@ -753,4 +753,16 @@ b
 100
 NULL
 DROP TABLE t1, t2;
+#
+# Bug #48475: DISTINCT is ignored with GROUP BY WITH ROLLUP
+#             and only const tables
+CREATE TABLE t1 (a INT);
+CREATE TABLE t2 (b INT);
+INSERT INTO t1 VALUES (1);
+INSERT INTO t2 VALUES (1);
+SELECT DISTINCT b FROM t1, t2 GROUP BY a, b WITH ROLLUP;
+b
+1
+NULL
+DROP TABLE t1, t2;
 End of 5.0 tests

mysql-test/t/olap.test

@@ -390,4 +390,17 @@ SELECT DISTINCT b FROM t1, t2 GROUP BY a, b WITH ROLLUP;
 
 DROP TABLE t1, t2;
 
+--echo #
+--echo # Bug #48475: DISTINCT is ignored with GROUP BY WITH ROLLUP
+--echo #             and only const tables
+
+CREATE TABLE t1 (a INT);
+CREATE TABLE t2 (b INT);
+INSERT INTO t1 VALUES (1);
+INSERT INTO t2 VALUES (1);
+
+SELECT DISTINCT b FROM t1, t2 GROUP BY a, b WITH ROLLUP;
+
+DROP TABLE t1, t2;
+
 --echo End of 5.0 tests

sql/sql_select.cc

@@ -929,14 +929,20 @@ JOIN::optimize()
     DBUG_RETURN(1);
   }
 
-  if (select_lex->olap == ROLLUP_TYPE && rollup_process_const_fields())
+  if (rollup.state != ROLLUP::STATE_NONE)
   {
-    DBUG_PRINT("error", ("Error: rollup_process_fields() failed"));
-    DBUG_RETURN(1);
+    if (rollup_process_const_fields())
+    {
+      DBUG_PRINT("error", ("Error: rollup_process_fields() failed"));
+      DBUG_RETURN(1);
+    }
+  }
+  else
+  {
+    /* Remove distinct if only const tables */
+    select_distinct= select_distinct && (const_tables != tables);
   }
 
-  /* Remove distinct if only const tables */
-  select_distinct= select_distinct && (const_tables != tables);
   thd_proc_info(thd, "preparing");
   if (result->initialize_tables(this))
   {
@@ -1216,11 +1222,14 @@ JOIN::optimize()
     - We are using an ORDER BY or GROUP BY on fields not in the first table
     - We are using different ORDER BY and GROUP BY orders
     - The user wants us to buffer the result.
+    When the WITH ROLLUP modifier is present, we cannot skip temporary table
+    creation for the DISTINCT clause just because there are only const tables.
   */
-  need_tmp= (const_tables != tables &&
+  need_tmp= ((const_tables != tables &&
 	     ((select_distinct || !simple_order || !simple_group) ||
 	      (group_list && order) ||
-	      test(select_options & OPTION_BUFFER_RESULT)));
+	      test(select_options & OPTION_BUFFER_RESULT))) ||
+             rollup.state != ROLLUP::STATE_NONE && select_distinct);
 
   // No cache for MATCH
   make_join_readinfo(this,