1 files changed, 30 insertions, 0 deletions
diff --git a/mysql-test/t/func_str.test b/mysql-test/t/func_str.test
index 46b4dc2e3f0..de954d2f60b 100644
--- a/mysql-test/t/func_str.test
+++ b/mysql-test/t/func_str.test
@@ -1611,6 +1611,36 @@ drop table t1,t2;
 select md5(_filename "a"), sha(_filename "a");
 
 --echo #
+--echo # MDEV-18881 Assertion `0' failed in make_sortkey upon SELECT with GROUP BY after LOAD DATA
+--echo #
+
+CREATE TABLE t1 (a BIT(22), b CHAR(8) NOT NULL, c CHAR(8));
+INSERT INTO t1 VALUES (0xA4B,'foo','qux');
+INSERT INTO t1 VALUES (0x8F5,'bar','foobar');
+INSERT INTO t1 VALUES (0x0, '', NULL);
+INSERT INTO t1 VALUES (0x4B, 'foo','qux');
+INSERT INTO t1 VALUES (0x8F5, 'bar', 'foobar');
+SET SESSION SQL_MODE= '';
+SELECT GROUP_CONCAT(c) AS f FROM t1 GROUP BY LPAD('foo', 20, b);
+DROP TABLE t1;
+SET SESSION SQL_MODE=DEFAULT;
+
+CREATE TABLE t1 AS SELECT
+  LPAD('a',10,' '),
+  RPAD('a',10,' '),
+  LPAD('a',10,'  '),
+  RPAD('a',10,'  '),
+  LPAD('a',10,NULL),
+  RPAD('a',10,NULL),
+  LPAD('a',10,''),
+  RPAD('a',10,''),
+  LPAD('a',10,RAND()),
+  RPAD('a',10,RAND());
+SHOW CREATE TABLE t1;
+DROP TABLE t1;
+
+
+--echo #
 --echo # End of 5.5 tests
 --echo #