Manual merge from mysql-trunk-merge.

Fix partition_column.test.

1 files changed, 11 insertions, 0 deletions

diff --git a/sql/opt_range.cc b/sql/opt_range.cc
index ce86fa535fe..61122b9892d 100644
--- a/sql/opt_range.cc
+++ b/sql/opt_range.cc
@@ -6067,6 +6067,17 @@ get_mm_leaf(RANGE_OPT_PARAM *param, COND *conf_func, Field *field,
     goto end;
   }
   field->table->in_use->variables.sql_mode= orig_sql_mode;
+
+  /*
+    Any sargable predicate except "<=>" involving NULL as a constant is always
+    FALSE
+  */
+  if (type != Item_func::EQUAL_FUNC && field->is_real_null())
+  {
+    tree= &null_element;
+    goto end;
+  }
+  
   str= (uchar*) alloc_root(alloc, key_part->store_length+1);
   if (!str)
     goto end;