用於多列查詢的SQL COUNT UNION

Question

我有一個查詢，它針對每個操作系統提供計算機的總數，程序XYZ的總數，免除需要程序XYZ的總數以及程序XYZ的總數（這是所有那些沒有XYZ程序並且沒有豁免的人）。我的數據位於兩個表格中，我希望可以使用聯合將數據合併爲單個結果。這裏是我的意思：

SELECT [OS Name], 
(SELECT COUNT (DISTINCT statement for total computers including a few joins and where)) 
(SELECT COUNT (DISTINCT statement for installed including a few joins and where)) 
(SELECT COUNT (DISTINCT statement for exempt including a few joins and where)) 
(SELECT COUNT (DISTINCT statement for missing including a few joins and where and a subquery)) 
FROM table 

我可以發佈真正的查詢，如果它是有幫助的。每個SELECT都是SELECT COUNT（DISTINCT Guid）FROM表JOIN table2 JOIN table3 WHERE condition1和condition2，其中一些使用WHERE語句中的子查詢。

它返回的結果是這樣的：

OS Name Total computers for this OS Program Installed Exempt Missing Program 
Microsoft Windows XP 4776 819 12 3955 
Windows 7 Enterprise 4 1 1 2 

第二運行查詢不同的數據庫：

OS Name Total computers for this OS Program Installed Exempt Missing Program 
Microsoft Windows XP 42 7 0 36 
Windows 7 Enterprise 2196 2143 21 33 

我的希望是，簡單地把兩個之間的聯盟將加起來的數量和我的數據將有兩行，但它有4個 - 每個操作系統列出兩次，每個數據庫一次。

我已經搜索谷歌和Stackoverflow，沒有運氣。

線程這樣SQL Count(*) on multiple tables這 two SQL COUNT() queries?似乎是正確的做法，但我掙扎，滿腦子都在，我怎麼能使用它，因爲我的計數複雜。對於簡單的列名不是COUNT（emp_id），而是使用JOIN，條件，有時候是子查詢。

Answer 1

使用你的聯合，但你需要根據這些結果進一步聚合。查詢近似。

SELECT 
    D.[OS Name] 
, SUM(D.[Computer Count]) AS [Computer Count] 
, D. ... 
FROM 
(
SELECT [OS Name], 
(SELECT COUNT (DISTINCT statement for total computers including a few joins and where)) 
(SELECT COUNT (DISTINCT statement for installed including a few joins and where)) 
(SELECT COUNT (DISTINCT statement for exempt including a few joins and where)) 
(SELECT COUNT (DISTINCT statement for missing including a few joins and where and a subquery)) 
FROM table 

UNION ALL 
SELECT [OS Name], 
(SELECT COUNT (DISTINCT statement for total computers including a few joins and where)) 
(SELECT COUNT (DISTINCT statement for installed including a few joins and where)) 
(SELECT COUNT (DISTINCT statement for exempt including a few joins and where)) 
(SELECT COUNT (DISTINCT statement for missing including a few joins and where and a subquery)) 
FROM table2 
) D 
GROUP BY 
    D.[OS Name]