将多个计数组合到一个查询中 - 分组依据

Question

我想将 3 个 SELECT 语句合并为一个：

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

但组合它们似乎总是返回错误：（操作数应包含 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

所以我尝试从各个语句中删除 JOIN 和 GROUP：

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

但这会返回所有内容的总数与用户细分（因为计数在 where 子句中没有说明用户 ID 或全名，毫无疑问）。

我觉得我很接近但错过了一些东西。谁能在这里指出我正确的方向？我只是想知道我做错了什么。

感谢您的宝贵时间。

Answer 1

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

Answer 2

我不知道您是否可以将这 3 个查询合并为一个统一查询。您有 3 个重叠的“where 子句”：

第一个查询：日期范围内的所有记录
第二个查询：所有在日期范围内但状态='C'的记录
第三个查询：所有在日期范围内但也有 cause_change=1 的记录

从逻辑上讲，第一个查询已经包含了来自第二个和第三个查询的所有记录，因此您将重复计算来自 #2 和 #3 的结果。

但是，如果您确实想将所有三个组合成一个结果，请执行外部查询方法：

SELECT sum(cnt), fullname
FROM (
    SELECT COUNT(A.id) as cnt, 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

    UNION

    ...
    WHERE status = 'C' AND DATE(origindate) BETWEEN '2011-03-01' AND '2011-07-11'

    UNION

    ...
    WHERE caused_change = 1 AND DATE(origindate) BETWEEN '2011-03-01' AND '2011-07-11'
) AS innerquery
GROUP BY fullname

注意第一个内部查询中count() 的别名。这是为了使计数字段在外部查询中显示为“cnt”。

Answer 3

UNION 和 SUM 应该可以完成这项工作。您的代码应如下所示：

 select sum(x.col1), x.fullname
from
(SELECT COUNT(A.id)as col1, 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
UNION
SELECT COUNT(A.id)as col1, 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
UNION
SELECT COUNT(A.id)as col1, 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
)x
group by x.fullname