用于多列查询的SQL COUNT UNION

Question

我有一个查询，它针对每个操作系统提供计算机的总数，程序XYZ的总数，免除需要程序XYZ的总数以及程序XYZ的总数（这是所有那些没有XYZ程序并且没有豁免的人）。我的数据位于两个表格中，我希望可以使用联合将数据合并为单个结果。这里是我的意思：

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 

我可以发布真正的查询，如果它是有帮助的。每个SELECT都是SELECT COUNT（DISTINCT Guid）FROM表JOIN table2 JOIN table3 WHERE condition1和condition2，其中一些使用WHERE语句中的子查询。

它返回的结果是这样的：

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 

第二运行查询不同的数据库：

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，简单地把两个之间的联盟将加起来的数量和我的数据将有两行，但它有4个 - 每个操作系统列出两次，每个数据库一次。

我已经搜索谷歌和Stackoverflow，没有运气。

线程这样SQL Count(*) on multiple tables这 two SQL COUNT() queries?似乎是正确的做法，但我挣扎，满脑子都在，我怎么能使用它，因为我的计数复杂。对于简单的列名不是COUNT（emp_id），而是使用JOIN，条件，有时候是子查询。

Answer 1

使用你的联合，但你需要根据这些结果进一步聚合。查询近似。

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]