选择两个表中的用户数

Question

我想计算两个表中相同用户 ID 的出现次数。 jos_findme 表中包含所有用户。另外两个也有“用户ID”列。

但我想要两张表中的总数。我试过了，但它不起作用？

SELECT 
    c.user_id, count(c.user_id) AS counter
FROM
    jos_findme as c
        LEFT JOIN
    jos_findme_bestof as b ON b.user_id = c.user_id
        LEFT JOIN
    jos_findme_pair as p ON p.user_id = c.user_id
WHERE
    c.user_id > 0
GROUP BY c.user_id
ORDER BY counter DESC
LIMIT 10

所有表都有“user_id”列。我只想将它们算在“jos_findme_bestof”和“jos_findme_pair”表中

Answer 1

我认为你可以这样做：

SELECT AA.user_id, AA.Acounter + BB.Bcounter
from     (SELECT a.user_id, count(a.user_id) AS Acounter
          FROM jos_findme_bestof as a
          GROUP BY a.user_id) as AA 
     Join  
        (SELECT b.user_id, count(b.user_id) AS Bcounter
          FROM jos_findme_pair as b
          GROUP BY b.user_id) as BB
     on AA.user_id = BB.user_id

如果您想要所有的 id（即 jos_findme_pair 中是否有 jos_findme_bestof 中没有的 id）- 使用 FULL OUTER JOIN

Answer 2

相关的子查询在这里可能很有用：

SELECT c.user_id, 
       (SELECT Count(*) 
        FROM   jos_findme_bestof b 
        WHERE  b.user_id = c.user_id), 
       (SELECT Count(*) 
        FROM   jos_findme_pair p 
        WHERE  p.user_id = c.user_id) 
FROM   jos_findme c 

Answer 3

试试这个：

SELECT c.user_id, (IFNULL(b.bCount, 0) + IFNULL(p.pCount, 0)) AS counter
FROM jos_findme AS c
LEFT JOIN (SELECT b.user_id, COUNT(1) bCount 
           FROM jos_findme_bestof b 
           GROUP BY b.user_id 
         ) AS b ON b.user_id = c.user_id 
LEFT JOIN (SELECT p.user_id, COUNT(1) pCount 
           FROM jos_findme_pair p 
           GROUP BY p.user_id 
         ) AS p ON p.user_id = c.user_id 
WHERE c.user_id > 0
GROUP BY c.user_id
ORDER BY counter DESC
LIMIT 10

Answer 4

试试这个

SELECT c.user_id,
       Users1 = (SELECT COUNT(*) FROM jos_findme_bestof b WHERE b.user_id = c.user_id),
       Users2 = (SELECT COUNT(*) FROM jos_findme_pair p WHERE p.user_id = c.user_id),
       TotalUser = (SELECT COUNT(*) FROM jos_findme_bestof b WHERE b.user_id = c.user_id)
       +
       (SELECT COUNT(*) FROM jos_findme_pair p WHERE p.user_id= c.user_id)
FROM   
jos_findme c

在这里， Users1 将返回来自jos_findme_bestof 的所有用户 Users2 将返回来自jos_findme_pair 的所有用户 TotalUser 将同时计入两个表

希望对你有帮助！ 谢谢。