merge

1 files changed, 9 insertions, 0 deletions

diff --git a/sql/sql_select.cc b/sql/sql_select.cc
index 02f2fc6bc9e..1a4c12d6940 100644
--- a/sql/sql_select.cc
+++ b/sql/sql_select.cc
@@ -1487,6 +1487,15 @@ JOIN::optimize()
     if (order)
     {
       /*
+        Do we need a temporary table due to the ORDER BY not being equal to
+        the GROUP BY? The call to test_if_skip_sort_order above tests for the
+        GROUP BY clause only and hence is not valid in this case. So the
+        estimated number of rows to be read from the first table is not valid.
+        We clear it here so that it doesn't show up in EXPLAIN.
+       */
+      if (need_tmp && (select_options & SELECT_DESCRIBE) != 0)
+        join_tab[const_tables].limit= 0;
+      /*
         Force using of tmp table if sorting by a SP or UDF function due to
         their expensive and probably non-deterministic nature.
       */