MERGE RETURNING PostgreSQL includes one merge support function that may be used in the RETURNING list of a command to identify the action taken for each row; see . Function Description merge_action merge_action ( ) text Returns the merge action command executed for the current row. This will be 'INSERT', 'UPDATE', or 'DELETE'. Example: 0 THEN UPDATE SET in_stock = true, quantity = s.quantity WHEN MATCHED THEN UPDATE SET in_stock = false, quantity = 0 WHEN NOT MATCHED THEN INSERT (product_id, in_stock, quantity) VALUES (s.product_id, true, s.quantity) RETURNING merge_action(), p.*; merge_action | product_id | in_stock | quantity --------------+------------+----------+---------- UPDATE | 1001 | t | 50 UPDATE | 1002 | f | 0 INSERT | 1003 | t | 10 ]]> Note that this function can only be used in the RETURNING list of a MERGE command. It is an error to use it in any other part of a query.