Manual merge

sql/sql_select.cc:
  Auto merged

mysql-test/r/distinct.result

@@ -472,3 +472,43 @@ id	IFNULL(dsc, '-')
 2	line number two
 3	line number three
 drop table t1;
+CREATE TABLE t1 (a int);
+INSERT INTO t1 VALUES (1),(2),(3),(4),(5);
+SELECT DISTINCT a, 1 FROM t1;
+a	1
+1	1
+2	1
+3	1
+4	1
+5	1
+SELECT DISTINCT 1, a FROM t1;
+1	a
+1	1
+1	2
+1	3
+1	4
+1	5
+CREATE TABLE t2 (a int, b int);
+INSERT INTO t2 VALUES (1,1),(2,2),(2,3),(2,4),(3,5);
+SELECT DISTINCT a, b, 2 FROM t2;
+a	b	2
+1	1	2
+2	2	2
+2	3	2
+2	4	2
+3	5	2
+SELECT DISTINCT 2, a, b FROM t2;
+2	a	b
+2	1	1
+2	2	2
+2	2	3
+2	2	4
+2	3	5
+SELECT DISTINCT a, 2, b FROM t2;
+a	2	b
+1	2	1
+2	2	2
+2	2	3
+2	2	4
+3	2	5
+DROP TABLE t1,t2;

mysql-test/t/distinct.test

@@ -341,4 +341,21 @@ insert into t1 values (1, "line number one"), (2, "line number two"), (3, "line
 select distinct id, IFNULL(dsc, '-') from t1;
 drop table t1;
 
+#
+# Test cases for #12625: DISTINCT for a list with constants
+#
+
+CREATE TABLE t1 (a int);
+INSERT INTO t1 VALUES (1),(2),(3),(4),(5);
+SELECT DISTINCT a, 1 FROM t1;
+SELECT DISTINCT 1, a FROM t1;
+
+CREATE TABLE t2 (a int, b int); 
+INSERT INTO t2 VALUES (1,1),(2,2),(2,3),(2,4),(3,5);
+SELECT DISTINCT a, b, 2 FROM t2;
+SELECT DISTINCT 2, a, b FROM t2;
+SELECT DISTINCT a, 2, b FROM t2;
+
+DROP TABLE t1,t2;
+
 # End of 4.1 tests

sql/sql_select.cc

@@ -12229,9 +12229,7 @@ create_distinct_group(THD *thd, Item **ref_pointer_array,
   li.rewind();
   while ((item=li++))
   {
-    if (item->const_item() || item->with_sum_func)
-      continue;
-    if (!item->marker)
+    if (!item->const_item() && !item->with_sum_func && !item->marker)
     {
       ORDER *ord=(ORDER*) thd->calloc(sizeof(ORDER));
       if (!ord)