MySQL - Làm cách nào để lọc và hiển thị giá trị tối đa từ một nhóm?

Một giải pháp khả thi là sử dụng HAVING và ALL

SELECT s.shopname AS "Store",
   e.empname AS "Employee",
   e1.empname AS "Manager",
   SUM(p.amount) AS "Total Sales"
FROM fss_Shop s
   JOIN fss_Employee e ON e.shopid = s.shopid
   JOIN fss_Payment p ON p.empnin = e.empnin
   JOIN fss_Employee e1 ON e1.empnin = e.mgrnin
GROUP BY e.empname, s.shopid
HAVING SUM(p.amount) >= ALL(
   SELECT SUM(p.amount)
   FROM fss_Employee e
   JOIN fss_Payment p ON p.empnin = e.empnin
   WHERE e.shopid = s.shopid
   GROUP BY e.empname
)

if ALL không hiệu quả với bạn. Bạn có thể thay đổi nó như thế này

SELECT s.shopname AS "Store",
   e.empname AS "Employee",
   e1.empname AS "Manager",
   SUM(p.amount) AS "Total Sales"
FROM fss_Shop s
   JOIN fss_Employee e ON e.shopid = s.shopid
   JOIN fss_Payment p ON p.empnin = e.empnin
   JOIN fss_Employee e1 ON e1.empnin = e.mgrnin
GROUP BY e.empname, e.shopid
HAVING SUM(p.amount) = (
   SELECT MAX(t.samount)
   FROM
   (
     SELECT SUM(p.amount) samount
     FROM fss_Employee emp
     JOIN fss_Payment p ON p.empnin = emp.empnin
     WHERE emp.shopid = e.shopid
     GROUP BY emp.empname
   ) t
)

ok và phiên bản tiếp theo tránh truy vấn con tương quan phía sau FROM

SELECT s.shopname AS "Store",
   e.empname AS "Employee",
   e1.empname AS "Manager",
   SUM(p.amount) AS "Total Sales"
FROM fss_Shop s
   JOIN fss_Employee e ON e.shopid = s.shopid
   JOIN fss_Payment p ON p.empnin = e.empnin
   JOIN fss_Employee e1 ON e1.empnin = e.mgrnin
GROUP BY e.empnin, e.shopid
HAVING (e.shopid, SUM(p.amount)) IN
(
  SELECT t.shopid, MAX(t.samount)
  FROM 
  (
     SELECT emp.shopid, SUM(p.amount) samount
     FROM fss_Employee emp
     JOIN fss_Payment p ON p.empnin = emp.empnin
     GROUP BY emp.empname, emp.shopid
  ) t
  GROUP BY t.shopid
)