在SQL中，如何获取具有特定列的最大值的行？

Question

我有一个问题：

SELECT COUNT(*) as votes, a.member_id 
FROM ballots a
WHERE ballot_id = 1
GROUP BY a.member_id

产生类似的东西：

votes  member_id
1      paul
5      mike
3      noynoy
10     andy
2      noel

我希望能够得到“andy”这一行，因为他获得了最高的“选票”。

如何更改查询以执行此操作？

提前感谢您的帮助：）

Answer 1

您可以使用ORDER BY然后DESC按降序从最高到最低票数进行排序。然后LIMIT结果只有一行（即最高）。

SELECT COUNT(*) as votes, a.member_id 
FROM ballots a
WHERE ballot_id = 1
GROUP BY a.member_id
ORDER BY votes DESC
LIMIT 1

Answer 2

SELECT COUNT(*) as votes, a.member_id 
FROM ballots a
WHERE ballot_id = 1
GROUP BY a.member_id
ORDER BY COUNT(*) DESC 
LIMIT 1

Answer 3

SELECT COUNT(*) as votes, a.member_id 
FROM ballots a 
WHERE ballot_id = 1 
GROUP BY a.member_id
ORDER BY votes DESC
LIMIT 1

Answer 4

SELECT COUNT(*) as votes, a.member_id 
FROM ballots a 
WHERE ballot_id = 1 
GROUP BY a.member_id
ORDER BY COUNT(*) DESC
LIMIT 1

Answer 5

如果重复最大值，则使用COUNT()将不会选择所有行。我的建议是使用MAX()

SELECT *
FROM ballots a
WHERE votes = (SELECT max(votes) FROM ballots)

Answer 6

使用专用view来计算投票

可能更容易获得

CREATE VIEW v_votes AS 
  SELECT member_id, ballot_id,  COUNT(*) AS votes FROM ballots GROUP BY member_id

然后使用 HAVING 子句

SELECT * FROM v_votes HAVING MAX(votes)