Question

我想得到user_id以及总和金额最大的用户的金额总和。我不能使用LIMIT，因为它只返回1条记录（多个用户的总和数量可能相同）

这是我的数据架构和一些记录

CREATE TABLE transactions (
  id BIGINT(20) NOT NULL AUTO_INCREMENT,
  user_id BIGINT(20) NOT NULL, 
  amount FLOAT NOT NULL, PRIMARY KEY (id)
);

INSERT INTO transactions (user_id, amount) VALUES 
(1, 1000),
(1, 1000),
(1, 1000),
(2, 2000),
(2, 1000),
(3, 1000);

以下是预期结果。

+---------+------+
| user_id | sum  |
+---------+------+
|       1 | 3000 |
|       2 | 3000 |
+---------+------+

我可以使用以下sql获得上述结果。但是，我不知道有没有更好的方法。是否有必要重复两次相同的子查询？感谢。

SELECT T1.user_id, T1.sum
FROM (
  SELECT user_id, SUM(amount) as sum
  FROM transactions
  GROUP BY user_id
) T1
WHERE T1.sum = (
  SELECT MAX(T2.sum)
  FROM (
    SELECT user_id, SUM(amount) as sum
    FROM transactions
    GROUP BY user_id
  ) T2
)
GROUP BY T1.user_id;

Answer 1

您可以将查询简化为

SELECT user_id, SUM(amount) as sum
FROM transactions
GROUP BY user_id
HAVING SUM(amount) = (      
  SELECT SUM(amount) as sum
  FROM transactions
  GROUP BY user_id
  ORDER BY SUM(amount) DESC 
  LIMIT 1
  )

MySQL - 查找分组SUM的MAX（无LIMIT）

1 个答案: