in the following mysql subquery how do I return 0 if the result is null?        (
           SELECT SUM(pl.amount)
           FROM payment_logs AS pl
           WHERE pl.user_uuid = users.uuid AND status = 'paid'
             AND pl.created > (
               SELECT MIN(pl4.created)
               FROM payment_logs AS pl4
               WHERE pl4.user_uuid = users.uuid
           )
       ) AS total_paid_since_cash_out,
