그냥 쌩조인 하지말고

SELECT * FROM paymentHistory AS t1
LEFT JOIN (
SELECT payNumber ,SUM((orderCount - orderDiscount) * menuCost)
FROM paymentDetails GROUP BY payNumber
) AS t2 ON t1.payNumber = t2.payNumber;


이렇게 고치면 작동되냐?

지금 대충 메모장에 끄적인거라 확인해볼수는 없다