在phpMyAdmin中自动化MySQL

I have a mysql database with three tables:

1. a list of users
2. a list of tasks
3. a table to say which users will do which task (join table)

Each day the list of tasks will change. So I will manually change this task list in phpmyadmin. What I want is for every task to be assigned to every user. I can see that this is manually possible in phpmyadmin but it would not really be feasible to do this manually for more than a few users.

Is there a quick piece of sql or something that can accomplish this? Or will I have to do a php script?

So far I just have some pseudo code that I thought about, wanted to make sure that this is the best approach before I commit myself:

Get current number of users
Get current number of tasks

From user 1 to the last user
     From task 1 to the last task
         assign current task in loop to current user in loop