how to i turn this query to a sub query SQL

Question

how can I change this query where I want to turn the max to a subquery where when I enter the sql the only thing that will appear is the id and first name.

SELECT staff.staff_id,staff.firstname,max(payment.amount)
from payment ,staff
where payment.staff_id=staff.staff_id

Answer 1

use explicit join

SELECT staff.staff_id,staff.firstname,max(payment.amount)
from payment join staff
on  payment.staff_id=staff.staff_id

but i think you want

   SELECT staff.staff_id,staff.firstname,p.amount
    from payment p join staff
    on  p.staff_id=staff.staff_id
    where p.amount= select max(amount) from payment 

Answer 2

You can try using correlated subquery

SELECT staff.staff_id,staff.firstname
from payment inner join staff
on payment.staff_id=staff.staff_id where payment.amount in (select max(payment.amount) from payment)

Answer 3

From JOIN to (correlated) sub-query:

SELECT staff.staff_id, staff.firstname,
       (SELECT MAX(payment.amount) 
        FROM payment
        WHERE payment.staff_id = staff.staff_id)
FROM staff