在SQL語法聯盟合併數據

Question

我正在做一個SQL語法聯盟，我想有這樣的結果：

+---------------+-----+---------+ 
|trkBusinessUnit| New | Pending | 
+---------------+-----+---------+ 
|  AIIB   2  0 | 
| Credit Control 1  3 | 
| Direct Center 1  2 | 
| Financial Ins  1  1 | 
| Motor Acclaim  1  0 | 
+-------------------------------+ 

從我的代碼：

SELECT trkBusinessUnit, Count(*) as New,0 as Pending 
FROM tblDTPTracker 
WHERE trkStatus = 'New' 
GROUP BY trkBusinessUnit 

UNION 

SELECT trkBusinessUnit,0 as New,Count(*) as Pending 
FROM tblDTPTracker 
WHERE trkStatus = 'Pending' 
GROUP BY trkBusinessUnit 

但隨後的電流輸出是：

+---------------+-----+---------+ 
|trkBusinessUnit| New | Pending | 
+---------------+-----+---------+ 
|  AIIB   2  0 | 
| Credit Control 1  0 | 
| Credit Control 0  3 | 
| Direct Center 1  0 | 
| Direct Center 0  2 | 
| Financial Ins  1  0 | 
| Financial Ins  0  1 | 
| Motor Acclaim  1  0 | 
+-------------------------------+ 

我錯過了什麼或做錯了什麼？好心提醒。

Answer 1

有（或已經）在以前的答案的一些語法問題，但兩者較早答案的意圖是正確的，你需要使用一個GROUP BY查詢，而不使用UNION - 它根本不會做你希望或期望的。

UNION或UNION ALL按行工作行，絕對不要用柱合併

因此，基於查詢MySQL的語法組可以是任何這些：使用

COUNT（）使用隱式NULL

SELECT 
     trkBusinessUnit 
    , COUNT(CASE WHEN trkStatus = 'New'  THEN 1 END) as New 
    , COUNT(CASE WHEN trkStatus = 'Pending' THEN 1 END) as Pending 
FROM tblDTPTracker 
GROUP BY trkBusinessUnit 
; 

COUNT（）顯式NULL

SELECT 
     trkBusinessUnit 
    , COUNT(CASE WHEN trkStatus = 'New'  THEN 1 ELSE NULL END) as New 
    , COUNT(CASE WHEN trkStatus = 'Pending' THEN 1 ELSE NULL END) as Pending 
FROM tblDTPTracker 
GROUP BY trkBusinessUnit 
; 

SUM（）來替代計數：

select 
     trkBusinessUnit 
    , sum(case when trkStatus = 'New'  then 1 else 0 end) as New 
    , sum(case when trkStatus = 'Pending' then 1 else 0 end) as Pending 
from tblDTPTracker 
where trkStatus in ('Pending', 'New') 
group by trkBusinessUnit 
; 

道歉兩者馬克Gravell &丹尼爾Gadawski誰之前此答案;這個答案是你的衍生物。

See this SQLFiddle demo of these queries

Answer 2

聯盟追加的行垂直地（指出UNION也只對不同的行; UNION ALL通吃行）。你想要的是兩個子查詢的full outer join，或者更復雜的select。我會選擇後者！

select tblDTPTracker, 
     sum(case trkStatus when 'New' then 1 else 0 end) as New, 
     sum(case trkStatus when 'Pending' then 1 else 0 end) as Pending 
from tblDTPTracker 
where trkStatus in ('Pending', 'New') 
group by tblDTPTracker 

完全外部聯接的做法是這樣的：

SELECT ISNULL(x.trkBusinessUnit, y.trkBusinessUnit) as trkBusinessUnit, 
     ISNULL(x.New, 0) as New, 
     ISNULL(y.Pending, 0) as Pending 
FROM (
    SELECT trkBusinessUnit, Count(1) as New 
    FROM tblDTPTracker 
    WHERE trkStatus = 'New' 
    GROUP BY trkBusinessUnit) x 
FULL OUTER JOIN (  
    SELECT trkBusinessUnit, Count(1) as Pending 
    FROM tblDTPTracker 
    WHERE trkStatus = 'Pending' 
    GROUP BY trkBusinessUnit) y on y.trkBusinessUnit = x.trkBusinessUnit 

Answer 3

如果我理解正確的話，你沒有使用一個工會。

嘗試：

SELECT 
    trkBusinessUnit, 
    COUNT(CASE WHEN trkStatus = 'New' THEN 1 ELSE NULL END) as New, 
    COUNT(CASE WHEN trkStatus = 'Pending' THEN 1 ELSE NULL END) as Pending 
FROM tblDTPTracker 
GROUP BY trkBusinessUnit