mysql – 将多个计数组合到一个查询中 – group by

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我有3个SELECT语句,我想组合成一个：

SELECT COUNT(A.id), CONCAT(B.fname,' ', B.lname) AS fullname 
FROM feedbacks A 
    INNER JOIN users B 
         ON A.userid = B.userid 
WHERE DATE(origindate) BETWEEN '2011-03-01' AND '2011-07-11' 
GROUP BY fullname

SELECT COUNT(A.id), CONCAT(B.fname,' ', B.lname) AS fullname 
FROM feedbacks A 
    INNER JOIN users B 
        ON A.userid = B.userid 
WHERE status = 'C' 
AND DATE(origindate) BETWEEN '2011-03-01' AND '2011-07-11' 
GROUP BY fullname`

SELECT COUNT(A.id), CONCAT(B.fname,' ', B.lname) AS fullname 
FROM feedbacks A 
    INNER JOIN users B ON A.userid = B.userid 
WHERE caused_change = 1 
AND DATE(origindate) BETWEEN '2011-03-01' AND '2011-07-11' 
GROUP BY fullname

但是组合它们似乎总是会返回一个错误:(操作数应该包含1列)

SELECT 
(SELECT COUNT(A.id), CONCAT(B.fname,' ', B.lname) AS fullname FROM feedbacks A INNER JOIN users B ON A.userid = B.userid WHERE DATE(origindate) BETWEEN '2011-03-01' AND '2011-07-11' GROUP BY fullname) AS T1,  
(SELECT COUNT(A.id), CONCAT(B.fname,' ', B.lname) AS fullname FROM feedbacks A INNER JOIN users B ON A.userid = B.userid WHERE status = 'C' AND DATE(origindate) BETWEEN '2011-03-01' AND '2011-07-11' GROUP BY fullname) AS T2,  
(SELECT COUNT(A.id), CONCAT(B.fname,' ', B.lname) AS fullname FROM feedbacks A INNER JOIN users B ON A.userid = B.userid WHERE caused_change = 1 AND DATE(origindate) BETWEEN '2011-03-01' AND '2011-07-11' GROUP BY fullname) AS T3

所以我尝试从单个语句中删除JOIN和GROUP来制作：

SELECT CONCAT(B.fname, ' ', B.lname) AS fullname,
(SELECT COUNT(A.id) FROM feedbacks A WHERE DATE(origindate) BETWEEN '2011-03-01' AND '2011-07-11') AS T1,  
(SELECT COUNT(A.id) FROM feedbacks A WHERE status = 'C' AND DATE(origindate) BETWEEN '2011-03-01' AND '2011-07-11') AS T2,
(SELECT COUNT(A.id) FROM feedbacks A WHERE caused_change = 1 AND DATE(origindate) BETWEEN '2011-03-01' AND '2011-07-11') AS T3
FROM feedbacks 
    INNER JOIN users B 
        ON feedbacks.userid = B.userid 
GROUP BY fullname

但是,这会返回所有内容的总计与用户的细分(因为计数在where子句中没有说明有关userid或fullname的内容,毫无疑问).

我觉得我很亲密但却缺少一些东西.谁能指出我在这里的正确方向？我只是想了解我做错了什么.

感谢您的时间.

解决方法:

最好的方法是使用条件SUM：

SELECT CONCAT(B.fname, ' ', B.lname) AS fullname,
       SUM(
           CASE WHEN DATE(origindate) BETWEEN '2011-03-01' AND '2011-07-11' 
           THEN 1 ELSE 0 END
       ) AS T1,
       SUM(
           CASE WHEN status = 'C' 
                 AND DATE(origindate) BETWEEN '2011-03-01' AND '2011-07-11' 
           THEN 1 ELSE 0 END
       ) AS T2,
       SUM(
           CASE WHEN caused_change = 1 
                 AND DATE(origindate) BETWEEN '2011-03-01' AND '2011-07-11' 
           THEN 1 ELSE 0 END
       ) AS T3
FROM feedbacks 
    INNER JOIN users B 
        ON feedbacks.userid = B.userid 
GROUP BY fullname

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