Question

How to achieve creating a trigger that ONLY updates if exist but NEVER inserts in mysql.

Thanks in advance.

Edit: I had not known that using update statement just update if exist, and does not throw any error if not exist. Thanks to @juergend

Answer 1

You can specify when a trigger gets fired: after update for instance.
When it got fired then you can do whatever you want, for instance update an other table.

Generally it works like that:

delimiter //
CREATE TRIGGER upd_trigger_name after UPDATE ON your_updated_table
   FOR EACH ROW
   BEGIN
        update other_table set col1 = a_value where id = other_value
   END;
//
delimiter ;

MySQL keywords:

update -> updates a record if found
insert -> inserts a new recods
replace -> updates if record found, inserts if not