How to use As in IF condition of mysql query?

I am working on ledger and my php code require query to identify whether its debit amount OR credit amount.

SELECT jobber, IF(Pay_type='Payable', amount AS credit_amount, amount AS debit_amount) FROM Jobber_payments

I have also tried this but not working for me. If there is any possibility in above query.

SELECT jobber, IF(Pay_type='Payable', credit_amount, debit_amount) AS amount_type
amount AS (SELECT amount_type)
FROM Jobber_payments

if condition(Pay_type='Payable') is true, it will pass

credit_amount will be a field name or column name and amount value 5000

else debit_amount will be a field name or column name and amount value 5000