結合兩個查詢來獲取分子，分母和分組

Question

我有兩個查詢。一個用於分子，另一個用於分母。如何組合這兩個查詢，以便我的結果是一個包含分子，分母和分組的表格？期望輸出的

例子：

Numerator | Denominator | Grouping 
----------|-------------|--------- 
30  | 51   | 1111 
172  | 216   | 2768 

Answer 1

你真的在同一個表中的兩個不同的聚合。出於很多原因，性能就是其中之一，您不希望將查詢分解爲兩部分，然後重新將它們連接在一起。你可以完成通過使用列級過濾，而不是WHERE子句篩選正確的結果：

select [officerID] 
    ,sum(case when [ST3ID] != '' then 1 else 0 end) as [Numerator] 
    ,count(*) as [Denomimator] 
FROM [dbo].[cobanVideos] 
WHERE [starting] > '6/1/2015 0:00:00 AM' 
AND [starting] < '7/1/2015 0:00:00 AM' 
GROUP BY [officerID] 

通過使用CASE語句來過濾在列級的數據，可以同時獲取這兩個值。您還可以通過加入以下作爲附加列計算百分比值（分子/ denminator）：

select [officerID] 
    ,sum(case when [ST3ID] != '' then 1 else 0 end) as [Numerator] 
    ,count(*) as [Denomimator] 
    ,case when count(*) <> 0 
      then sum(case when [ST3ID] != '' then 1.0 else 0 end)/count(*) 
      else 0 
     end as [Pct ST3] 
FROM [dbo].[cobanVideos] 
WHERE [starting] > '6/1/2015 0:00:00 AM' 
AND [starting] < '7/1/2015 0:00:00 AM' 
GROUP BY [officerID] 

SQL窗口功能，給你一個整體的其他的工具集，用於在不同層次聚集的聚集工作，所有在一個查詢中。如果你有興趣，我可以跟進一個例子，說明你如何計算每位軍官的軍官比例，並且確定每個軍官對總數的貢獻百分比，所有這些都用一個SELECT。

Answer 2

使用JOIN：

Select numerator.Count, denominator.Count, numerator.officerID from (SELECT COUNT() as Count, officerID FROM [dbo].[cobanVideos] WHERE starting > '6/1/2015 0:00:00 AM' AND starting < '7/1/2015 0:00:00 AM' AND ST3ID != '' GROUP BY officerID) numerator Join (SELECT COUNT() as Count, officerID FROM [dbo].[cobanVideos] WHERE starting > '6/1/2015 0:00:00 AM' AND starting < '7/1/2015 0:00:00 AM' GROUP BY officerID) denominator On numerator.officerId = denominator.officerId 

Answer 3

對於你的結果想，你必須使用一個案例Statment

這裏是例子

SELECT 
SUM(CASE WHEN ST3ID != '' THEN 1 ELSE 0 END) [NUMERATOR] , 
COUNT(*)          [DENOMINATOR], 
officerID          [GROUPING] 
FROM [dbo].[cobanVideos] 
WHERE [starting] > '6/1/2015 0:00:00 AM' 
AND [starting] < '7/1/2015 0:00:00 AM' 
GROUP BY GROUPINGID 

爲了回答你的問題，你必須使用一個加入statment

例子：

SELECT 
    ISNULL(numerator,0)    as [Numerator], 
    ISNULL(Denominator,0)   as [Denominator], 
    ISNULL(a.officerID,b.officerID) as [Grouping] 
FROM 
(SELECT COUNT(*) numerator, officerID ....) AS [TableA] 
FULL JOIN 
(SELECT COUNT(*) Denominator, officerID ....) AS [TableB] 
ON [TableA].[officerID] = [TableB].[officerID]