將多個計數組合到一個查詢中 - 分組依據

Question

我有 3 個 SELECT 語句我想合並為一個：

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

但是將它們組合起來似乎總是返回錯誤：（操作數應包含 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

因此，我嘗試從各個語句中刪除 JOIN 和 GROUP 以進行：

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

但這會返回所有內容的總數與用戶細分的總數（因為毫無疑問，計數在 where 子句中沒有說明用戶 ID 或全名的任何內容）。

我覺得我很接近但錯過了一些東西。 誰能在這里指出我正確的方向？ 我只是想知道我做錯了什么。

感謝您的時間。

Answer 1

最好的方法是使用條件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將這 3 個查詢合並為一個統一查詢。 您有 3 個重疊的“where 子句”：

第一個查詢：日期范圍內的所有記錄
第二個查詢：在日期范圍內但也有 status='C' 的所有記錄
第三個查詢：在日期范圍內但也有 cause_change=1 的所有記錄

從邏輯上講，第一個查詢已經包含了來自第二個和第三個查詢的所有記錄，因此您將重復計算來自 #2 和 #3 的結果。

但是，如果您確實想將所有三個組合成一個結果，請執行外部查詢方法：

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

請注意第一個內部查詢中count()的別名。 這是為了使計數字段在外部查詢中顯示為“cnt”。

Answer 3

UNION 和 SUM 應該做這項工作。 您的代碼應如下所示：

 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