I am not sure if you need to do any work in PHP or not, but if you don't, you can make use of MySQL's Event Scheduler. This will allow you to run scheduled jobs within your database. Read more about the syntax for creating such events here. Here is an example:
CREATE EVENT some_event
ON SCHEDULE AT 12:34:00 EVERY DAY
DO
UPDATE my_schema.my_table SET my_column = my_column + 1;
I didn't test it, so hopefully it works.
Alternatively, you can make a cronjob on your server. Most shared hosting providers also allow you to do this. If you are not using shared hosting, you could have the cronjob run something like this:
mysql -u username -p password -e "UPDATE my_schema.my_table SET my_column = my_column + 1";
Again, not tested, but it should point you in the right direction.
Another option is to use a cronjob together with cURL
such that when the cronjob is run, an URL is requested.
curl http://yourdomain.com/yourtask
Then in Zend Framework, you could have a yourtask
route or just use module, controller and action in the URL. Then you would send off the database query from PHP and Zend Framework.
You could also just have a standalone PHP script somewhere else that is called by cURL. Or better yet, by PHP directly. Then it does not have to be available to the world.
As you see, you have quite a few options. Choose the one that is right in your case. We don't have enough details to make this choice.