
including virtual columns and aliases, expressions which use various operators
such as bitwise, logical and arithmetic operators, string functions, date-time
functions, numeric functions, control flow functions, secondary functions and
stored functions. Along with this, statements which have subqueries and
prepared statements can also be used.

Examples
--------

Simple REPLACE statement

REPLACE INTO t2 VALUES (1,'Leopard'),(2,'Dog') RETURNING id2, id2+id2 
as Total ,id2|id2, id2&&id2;
+-----+-------+---------+----------+
| id2 | Total | id2|id2 | id2&&id2 |
+-----+-------+---------+----------+
|   1 |     2 |       1 |        1 |
|   2 |     4 |       2 |        1 |
+-----+-------+---------+----------+

Using stored functions in RETURNING

DELIMITER |
CREATE FUNCTION f(arg INT) RETURNS INT
  BEGIN
   RETURN (SELECT arg+arg);
  END|

DELIMITER ;
PREPARE stmt FROM "REPLACE INTO t2 SET id2=3, animal2='Fox' RETURNING f2(id2),
UPPER(animal2)";

EXECUTE stmt;
+---------+----------------+
| f2(id2) | UPPER(animal2) |
+---------+----------------+
|       6 | FOX            |
+---------+----------------+

Subqueries in the statement

REPLACE INTO t1 SELECT * FROM t2 RETURNING (SELECT id2 FROM t2 WHERE 
id2 IN (SELECT id2 FROM t2 WHERE id2=1)) AS new_id;
+--------+
| new_id |
+--------+
|      1 |
|      1 |
|      1 |
|      1 |
+--------+

Subqueries in the RETURNING clause that return more than one row or column
cannot be used..

Aggregate functions cannot be used in the RETURNING clause. Since aggregate
functions work on a set of values and if the purpose is to get the row count,
ROW_COUNT() with SELECT can be used, or it can be used in
REPLACE...SELECT...RETURNING if the table in the RETURNING clause is not the
same as the REPLACE table. ECT...RETURNING if the table in the RETURNING
clause is not the same as the REPLACE table.

URL: https://mariadb.com/kb/en/replace/