How to add “ON update current timestamp” to existing table column

Question

i have column say ts_activity with datatype timestamp in MYSQL and default value to current timestamp. I want to add on update apply current time stamp to this column value.

Answer 1

Try this query -

ALTER TABLE table_name
  CHANGE COLUMN column_name column_name TIMESTAMP NULL DEFAULT CURRENT_TIMESTAMP ON UPDATE CURRENT_TIMESTAMP;

Note, in the table only one field can be with 'ON UPDATE CURRENT_TIMESTAMP' option.

Answer 2

Devart's suggestion will work, but I prefer to use MODIFY COLUMN instead of CHANGE COLUMN if I'm not renaming the column.

I also assume that your ts_activity column is not nullable since you have a default, so I am setting it to NOT NULL, but that's up to you.

This is the statement I would use:

ALTER TABLE your_table
  MODIFY COLUMN ts_activity TIMESTAMP NOT NULL DEFAULT CURRENT_TIMESTAMP ON UPDATE CURRENT_TIMESTAMP;