Administration of MySQL Users
Can you please clarify Users vs Programmers? Typically this is how it is done:

1) Create three identical schemas and name them PROD, QA and DEV. Their names are self explanatory.

2) Create a dbuser for the application (PHP) use on each of them. If your app is MYAPP, name the dbuser myapp. This is the login the application uses on behalf of every application user.

3) Create a dbuser called dbadmin on each of them and give it to your DBA.

4) Create a dbuser called myapp_dev on each of them and give it to your developers.