How to set DEFAULT ON UPDATE CURRENT_TIMESTAMP + 5 MINUTES? - mysql

Question

I have a table with three columns:
"code" column (integers)
two DATETIME columns ("created_at", "expires_at")
"created_at" column default value is CURRENT_TIMESTAMP.
"expires_at" column default value is CURRENT_TIMESTAMP + INTERVAL 5 MINUTE.
So far no problem.
Now I would like the ON UPDATE values to be the same as the default ones:
for the "created_at" column, ON UPDATE CURRENT_TIMESTAMP works like a charm.
for the "expires_at" column, I can't get ON UPDATE (CURRENT_TIMESTAMP + INTERVAL 5 MINUTE)
The query to create the "expires_at" column
ALTER TABLE codes ADD expires_at DATETIME DEFAULT (CURRENT_TIMESTAMP + INTERVAL 5 MINUTE);
work successfully.
When I try to add ON UPDATE,
ALTER TABLE codes ADD expires_at DATETIME DEFAULT (CURRENT_TIMESTAMP + INTERVAL 5 MINUTE) ON UPDATE (CURRENT_TIMESTAMP + INTERVAL 5 MINUTE);
this query doesn't work.
It returns the error: ERROR 1064 (42000): You have an error in your SQL syntax; check the manual that corresponds to your MySQL server version for the right syntax to use near '(CURRENT_TIMESTAMP + INTERVAL 5 MINUTE)' at line 1
I also tried with:
NOW() instead of CURRENT_TIMESTAMP
DATE_ADD() and ADDTIME() functions
but these solutions also do not work.

Answer 1

Such expression in ON UPDATE is not allowed. You may use intermediate updated_at column and generated expired_at column.
DEMO
CREATE TABLE test (
id INT PRIMARY KEY,
created_at DATETIME DEFAULT CURRENT_TIMESTAMP,
updated_at DATETIME DEFAULT CURRENT_TIMESTAMP
ON UPDATE CURRENT_TIMESTAMP,
expired_at DATETIME GENERATED ALWAYS AS (updated_at + INTERVAL 3 MINUTE)
);
INSERT INTO test (id) VALUES (1);
SELECT *, SLEEP(2) FROM test;
id
created_at
updated_at
expired_at
SLEEP(2)
1
2023-01-06 14:00:35
2023-01-06 14:00:35
2023-01-06 14:03:35
0
UPDATE test SET id = 2 WHERE id = 1;
SELECT * FROM test;
id
created_at
updated_at
expired_at
2
2023-01-06 14:00:35
2023-01-06 14:00:37
2023-01-06 14:03:37
fiddle