Drop Down List Not Getting Records

If i have a drop down list containing employee type names e.g. Plumber plasterer bricklayer from the employee type table. How would i select the bricklayer and bring back records associated with the selected employee type . I have done a query to go and get the records for the employee type and it works for one employee type.

But I cannot get the button to go and get the records when i select different employee types from the drop down list. I could add loads of buttons with the same query and change the employee type but looks a bit crowded and untidy. Am i missing something simple or is it just complicated.