Hi, I'll give you a companion example, I try to obtain from the table of clients only those that are as active in my database and that are for example the CDMX.
SELECT * FROM tb_clientes WHERE cliente_status = 1 AND residencia_cliente = 'CDMX';
With the above and your combobox will not be filled with all the info. of your table if not only with what is relevant for you to show in the user's view.
Greetings