adding test

src/test/regress/expected/merge_vcore.out

@@ -476,6 +476,77 @@ WHEN MATCHED THEN DO NOTHING;
                                  Filter: ('2'::bigint = id)
 (11 rows)
 
+DROP TABLE IF EXISTS source;
+DROP TABLE IF EXISTS target;
+-- Bug Fix Test as part of this PR
+-- Test 1
+CREATE TABLE source (
+    id int,
+    age int,
+    salary int
+);
+CREATE TABLE target (
+    id int,
+    age int,
+    salary int
+);
+SELECT create_distributed_table('source', 'id', colocate_with=>'none');
+ create_distributed_table
+---------------------------------------------------------------------
+
+(1 row)
+
+SELECT create_distributed_table('target', 'id', colocate_with=>'none');
+ create_distributed_table
+---------------------------------------------------------------------
+
+(1 row)
+
+INSERT INTO source (id, age, salary) VALUES  (1,30, 100000);
+MERGE INTO ONLY target USING source ON (source.id = target.id)
+WHEN NOT MATCHED THEN
+INSERT (id, salary) VALUES (source.id, source.salary);
+SELECT * FROM TARGET;
+ id | age | salary
+---------------------------------------------------------------------
+  1 |     | 100000
+(1 row)
+
+DROP TABLE IF EXISTS source;
+DROP TABLE IF EXISTS target;
+-- Test 2
+CREATE TABLE source (
+    id int,
+    age int,
+    salary int
+);
+CREATE TABLE target (
+    id int,
+    age int,
+    salary int
+);
+SELECT create_distributed_table('source', 'id', colocate_with=>'none');
+ create_distributed_table
+---------------------------------------------------------------------
+
+(1 row)
+
+SELECT create_distributed_table('target', 'id', colocate_with=>'none');
+ create_distributed_table
+---------------------------------------------------------------------
+
+(1 row)
+
+INSERT INTO source (id, age, salary) VALUES  (1,30, 100000);
+MERGE INTO ONLY target USING source ON (source.id = target.id)
+WHEN NOT MATCHED THEN
+INSERT (salary, id) VALUES (source.salary, source.id);
+SELECT * FROM TARGET;
+ id | age | salary
+---------------------------------------------------------------------
+  1 |     | 100000
+(1 row)
+
 DROP TABLE IF EXISTS source;
 DROP TABLE IF EXISTS target;
 DROP SCHEMA IF EXISTS merge_vcore_schema CASCADE;