MySQL trigger: Update when reaching a certain date

Question

I want to create a MySQL trigger that updates a table everytime one of the datetime rows in a different table reaches a datetime lower than now.

How would I accomplish this? Is that even possible?

To illustrate:

table_1                           table_2      
--------   -------------------    --------   -
id         1                      id         1
datetime   2011-05-10 11:11:11    counter    1

So, when time passes and NOW() becomes 2011-05-10 11:11:12, then I want to have the counter upped by 1.

Answer 1

You should be able to do it using a trigger and the event scheduler:
- create a trigger on the table that is fired on every update / insert
- this trigger creates a scheduled event that occurs at the datetime of the row and updates your second table

Answer 2

You could use MySQL's Event Scheduler.