[英]SELECT COUNT() INSIDE A SELECT MAX() SQL
我在数据库中有一个名为player_mast
表(数据只是一个例子),我想找到为 2016 年欧洲杯提供最多球员的俱乐部。
玩家 ID | country_id | 球衣号码 | 参赛者姓名 | posi_to_play | dt_of_bir | 年龄 | play_club |
---|---|---|---|---|---|---|---|
1231 | 1231 | 10 | 冒险 | 前锋 | 2/3/1991 | 33 | 切尔西 |
为什么这个查询不起作用? 在我看来是正确的:
SELECT playing_club, MAX(NumberOfPlayerForTeam)
FROM (
SELECT playing_club, COUNT(player_id) AS NumberOfPlayerForTeam
FROM player_mast
GROUP BY(playing_club))
GROUP BY(playing_club);
试试这个
SELECT playing_club, NumberOfPlayerForTeam<br>
FROM (<br>
SELECT playing_club, COUNT(player_id) AS NumberOfPlayerForTeam<br>
FROM player_mast<br>
GROUP BY(playing_club))<br>
ORDER BY NumberOfPlayerForTeam DESC LIMIT 1;
如果您想要表格中行数最多的俱乐部,您可以使用rank()
:
SELECT pm.*
FROM (SELECT playing_club, COUNT(*) AS NumberOfPlayerForTeam,
RANK() OVER (ORDER BY COUNT(*) DESC) as seqnum
FROM player_mast
GROUP BY playing_club
) pm
WHERE seqnum = 1;
笔记:
COUNT(<column name>)
计算COUNT(<column name>)
中非NULL
值的数量。 不需要做这个额外的检查; COUNT(*)
做你想要的。GROUP BY
键周围不需要括号。
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