diff --git a/src/test/regress/expected/pg_compatibility.out b/src/test/regress/expected/pg_compatibility.out
index 1dba798d5..02c949168 100644
--- a/src/test/regress/expected/pg_compatibility.out
+++ b/src/test/regress/expected/pg_compatibility.out
@@ -28,4 +28,18 @@ select ''::int;
 ERROR:  invalid input syntax for integer: ""
 LINE 1: select ''::int;
                ^
-CONTEXT:  referenced column: int4
\ No newline at end of file
+CONTEXT:  referenced column: int4
+
+select concat_ws('','ABCDE', 2, null, 22);
+ concat_ws
+-----------
+ ABCDE222
+(1 row)
+
+
+select concat_ws(null,'ABCDE', 2, null, 22);
+ concat_ws
+-----------
+ 
+(1 row)
+
diff --git a/src/test/regress/sql/pg_compatibility.sql b/src/test/regress/sql/pg_compatibility.sql
index 3db2d3bb2..93a003df6 100644
--- a/src/test/regress/sql/pg_compatibility.sql
+++ b/src/test/regress/sql/pg_compatibility.sql
@@ -13,4 +13,8 @@ select concat(null,'','','') is null;
 
 select concat('','') is null;
 
-select ''::int;
\ No newline at end of file
+select ''::int;
+
+select concat_ws('','ABCDE', 2, null, 22);
+
+select concat_ws(null,'ABCDE', 2, null, 22);
\ No newline at end of file