Bug#25376: Incomplete setup of ORDER BY clause results in a wrong result.

Functions over sum functions wasn't set up correctly for the ORDER BY clause
which leads to a wrong order of the result set.

The split_sum_func() function is called now for each ORDER BY item that
contains a sum function to set it up correctly.

mysql-test/r/order_by.result

@@ -926,3 +926,11 @@ NULL
 2
 3
 DROP TABLE t1,t2,t3,t4;
+create table t1 (a int, b int, c int);
+insert into t1 values (1,2,3), (9,8,3), (19,4,3), (1,4,9);
+select a,(sum(b)/sum(c)) as ratio from t1 group by a order by sum(b)/sum(c) asc;
+a	ratio
+1	0.5000
+19	1.3333
+9	2.6667
+drop table t1;

mysql-test/t/order_by.test

@@ -640,3 +640,11 @@ SELECT t2.b FROM t1 LEFT JOIN (t2, t3 LEFT JOIN t4 ON t3.a=t4.a)
 ON (t1.a=t2.a AND t1.b=t3.b) order by t2.b;
 
 DROP TABLE t1,t2,t3,t4;
+
+#
+# Bug#25376: Incomplete setup of ORDER BY clause results in a wrong result.
+#
+create table t1 (a int, b int, c int);
+insert into t1 values (1,2,3), (9,8,3), (19,4,3), (1,4,9);
+select a,(sum(b)/sum(c)) as ratio from t1 group by a order by sum(b)/sum(c) asc;
+drop table t1;

sql/sql_select.cc

@@ -455,6 +455,17 @@ JOIN::prepare(Item ***rref_pointer_array,
 
   select_lex->fix_prepare_information(thd, &conds, &having);
 
+  if (order)
+  {
+    ORDER *ord;
+    for (ord= order; ord; ord= ord->next)
+    {
+      Item *item= *ord->item;
+      if (item->with_sum_func && item->type() != Item::SUM_FUNC_ITEM)
+        item->split_sum_func(thd, ref_pointer_array, all_fields);
+    }
+  }
+
   if (having && having->with_sum_func)
     having->split_sum_func2(thd, ref_pointer_array, all_fields,
                             &having, TRUE);