1 files changed, 15 insertions, 0 deletions
diff --git a/mysql-test/t/alter_table.test b/mysql-test/t/alter_table.test
index 5534aa0a234..bf599818ad6 100644
--- a/mysql-test/t/alter_table.test
+++ b/mysql-test/t/alter_table.test
@@ -1062,3 +1062,18 @@ ALTER TABLE t1 CHANGE COLUMN f1 f1_no_real_change TIMESTAMP NULL DEFAULT NULL;
 DROP TABLE t1;
 
 --echo End of 5.1 tests
+
+#
+# Bug #31031 ALTER TABLE regression in 5.0
+#
+#  The ALTER TABLE operation failed with 
+#  ERROR 1089 (HY000): Incorrect sub part key; ...
+#
+CREATE TABLE t1(c CHAR(10), 
+  i INT UNSIGNED AUTO_INCREMENT NOT NULL PRIMARY KEY);
+INSERT INTO t1 VALUES('a',2),('b',4),('c',6);
+ALTER TABLE t1
+  DROP i,
+  ADD i INT UNSIGNED NOT NULL AUTO_INCREMENT,
+  AUTO_INCREMENT = 1;
+DROP TABLE t1;