subselect.test, subselect.result:

  Added a test case for bug #12392.
item_cmpfunc.cc:
  Fixed bug #12392.
  Missing handling of rows containing NULL components
  when evaluating IN predicates caused a crash.

mysql-test/r/subselect.result

@@ -2742,3 +2742,9 @@ one	two	flag
 5	6	N
 7	8	N
 DROP TABLE t1,t2;
+CREATE TABLE t1 (a char(5), b char(5));
+INSERT INTO t1 VALUES (NULL,'aaa'), ('aaa','aaa');
+SELECT * FROM t1 WHERE (a,b) IN (('aaa','aaa'), ('aaa','bbb'));
+a	b
+aaa	aaa
+DROP TABLE t1;

mysql-test/t/subselect.test

@@ -1770,4 +1770,15 @@ SELECT * FROM t1
 
 DROP TABLE t1,t2;
 
+#
+# Bug #12392: where cond with IN predicate for rows and NULL values in table 
+#
+
+CREATE TABLE t1 (a char(5), b char(5));
+INSERT INTO t1 VALUES (NULL,'aaa'), ('aaa','aaa');
+
+SELECT * FROM t1 WHERE (a,b) IN (('aaa','aaa'), ('aaa','bbb'));
+
+DROP TABLE t1;
+
 # End of 4.1 tests

sql/item_cmpfunc.cc

@@ -1551,6 +1551,8 @@ in_row::~in_row()
 byte *in_row::get_value(Item *item)
 {
   tmp.store_value(item);
+  if (item->is_null())
+    return 0;
   return (byte *)&tmp;
 }