Question

这是我的代码：

SELECT *, cr.club_winner AS 'club_winner', COUNT(club_winner) AS 'count_cw'
FROM clubs c
JOIN club_results cr 
WHERE c.club_id = cr.club_winner AND c.club_group = '1'
GROUP BY cr.club_winner
ORDER BY count_cw DESC, club_name

我在一个表中有俱乐部名称的行，在第二个表中有club_winner id。在表格中，我想展示现场排名，如果俱乐部从未成为赢家，则显示为“0”。不知道该怎么做。

现在它只显示至少一次获胜者的俱乐部。

我试图添加'case'，但id不起作用

Answer 1

从LEFT JOIN开始。我认为你想要的查询是这样的：

SELECT c.*, COUNT(cr.club_winner) AS count_wins
FROM clubs c LEFT JOIN
     club_results cr 
     ON c.club_id = cr.club_winner 
WHERE c.club_group = '1'
GROUP BY c.club_id
ORDER BY count_cw DESC, club_name;

Answer 2

将您的where条款更改为on条款，并将您的加入更改为left join：

SELECT *, cr.club_winner AS 'club_winner', COUNT(club_winner) AS 'count_cw'
FROM clubs c
LEFT JOIN club_results cr ON c.club_id = cr.club_winner AND c.club_group = '1'
GROUP BY cr.club_winner
ORDER BY count_cw DESC, club_name

Answer 3

如果你没有第二张表中的值

，你应该使用左连接

SELECT *, cr.club_winner AS club_winner, COUNT(club_winner) AS count_cw
FROM clubs c
LEFT JOIN club_results cr on c.club_id = cr.club_winner AND c.club_group = '1'

GROUP BY cr.club_winner
ORDER BY count_cw DESC, club_name

JOIN显示行，即使它为null

3 个答案: