group_by.result, group_by.test:

  Added a test case for bug #8614.
sql_select.cc:
  Fixed bug #8614.
  SELECT DISTINCT ... GROUP BY 'const' must be equivalent to
  SELECT ... GROUP BY 'const'.


sql/sql_select.cc:
  Fixed bug #8614.
  SELECT DISTINCT ... GROUP BY 'const' must be equivalent to
  SELECT ... GROUP BY 'const'.
mysql-test/t/group_by.test:
  Added a test case for bug #8614.
mysql-test/r/group_by.result:
  Added a test case for bug #8614.

mysql-test/r/group_by.result

@@ -722,3 +722,13 @@ WHERE hostname LIKE '%aol%'
     GROUP BY hostname;
 hostname	no
 cache-dtc-af05.proxy.aol.com	1
+DROP TABLE t1;
+CREATE TABLE t1 (a  int, b int);
+INSERT INTO t1 VALUES (1,2), (1,3);
+SELECT a, b FROM t1 GROUP BY 'const';
+a	b
+1	2
+SELECT DISTINCT a, b FROM t1 GROUP BY 'const';
+a	b
+1	2
+DROP TABLE t1;

mysql-test/t/group_by.test

+
 # Initialise
 --disable_warnings
 drop table if exists t1,t2,t3;
@@ -524,7 +525,7 @@ select min(b) from t1;
 drop table t1;
 
 #
-# Test for bug #11088: GROUP BY a BLOB colimn with COUNT(DISTINCT column1) 
+# Test for bug #11088: GROUP BY a BLOB column with COUNT(DISTINCT column1) 
 #
 
 CREATE TABLE t1 (id int PRIMARY KEY, user_id int, hostname longtext);
@@ -539,3 +540,15 @@ SELECT hostname, COUNT(DISTINCT user_id) as no FROM t1
   WHERE hostname LIKE '%aol%'
     GROUP BY hostname;
 
+DROP TABLE t1;
+
+#
+# Test for bug #8614: GROUP BY 'const with DISTINCT  
+#
+
+CREATE TABLE t1 (a  int, b int);
+INSERT INTO t1 VALUES (1,2), (1,3);
+SELECT a, b FROM t1 GROUP BY 'const';
+SELECT DISTINCT a, b FROM t1 GROUP BY 'const';
+
+DROP TABLE t1;

sql/sql_select.cc

@@ -676,9 +676,14 @@ JOIN::optimize()
       DBUG_RETURN(1);
   }
   simple_group= 0;
-  group_list= remove_const(this, group_list, conds,
+  {
+    ORDER *old_group_list;
+    group_list= remove_const(this, (old_group_list= group_list), conds,
                              rollup.state == ROLLUP::STATE_NONE,
 			     &simple_group);
+    if (old_group_list && !group_list)
+      select_distinct= 0;
+  }
   if (!group_list && group)
   {
     order=0;					// The output has only one row