Question

我试图了解位于农村或城市地区的组织的比例 - 类别＆＃39;乡村性＆＃39;有乡村＆＃39; Urban＆＃39; Urban＆＃39;或者＆＃39; NULL＆＃39;。我可以计算出城市＆＃39;的百分比。和乡村＆＃39;作为所有值的百分比，但我想要排除所有出现的＆＃39; NULL＆＃39;值。

目前我有：

SELECT Geography_Rurality_DEFRA_Grouped as 'Type',
COUNT(*) as 'Count',
(COUNT(Geography_Rurality_DEFRA_Grouped)* 100 / (SELECT COUNT(*) FROM [SWFC_Project].[dbo].[Lookup_SchoolLevelIndicators])) AS Perc 
FROM [SWFC_Project].[dbo].[Lookup_SchoolLevelIndicators] 
WHERE Geography_Rurality_DEFRA_Grouped IS NOT NULL 
GROUP BY [Geography_Rurality_DEFRA_Grouped]
ORDER BY 'Count' desc, Geography_Rurality_DEFRA_Grouped

我的输出是：

Type | Count | Perc
-------------------
Urban| 78117 | 72
Rural| 27693 | 25

然而，百分比只增加了97％，而我想要＆＃39; Urban＆＃39;和乡村＆＃39;到我的100％，排除＆＃39; NULL＆＃39;值。

如果有任何不同，我会使用SSMS。

Answer 1

在子查询中，您必须在IS NOT NULL上添加条件，如下所示：

SELECT Geography_Rurality_DEFRA_Grouped as 'Type',
COUNT(*) as 'Count',
(COUNT(Geography_Rurality_DEFRA_Grouped)* 100 / 
(SELECT COUNT(*) 
FROM [SWFC_Project].[dbo].[Lookup_SchoolLevelIndicators]
WHERE Geography_Rurality_DEFRA_Grouped IS NOT NULL) AS Perc 
FROM [SWFC_Project].[dbo].[Lookup_SchoolLevelIndicators] 
WHERE Geography_Rurality_DEFRA_Grouped IS NOT NULL 
GROUP BY [Geography_Rurality_DEFRA_Grouped]
ORDER BY 'Count' desc, Geography_Rurality_DEFRA_Grouped

Answer 2

您只需切换到COUNT(Geography_Rurality_DEFRA_Grouped)而不是COUNT(*)，这会排除NULL。

但是SQL Server支持Windowed Aggregate Function，你只需要一个 GROUP SUM ：

SELECT Geography_Rurality_DEFRA_Grouped AS 'Type',
   COUNT(Geography_Rurality_DEFRA_Grouped) AS 'Count',

   100 * COUNT(*) / SUM(COUNT(*)) OVER () AS Perc 
FROM [SWFC_Project].[dbo].[Lookup_SchoolLevelIndicators] 
WHERE Geography_Rurality_DEFRA_Grouped IS NOT NULL 
GROUP BY [Geography_Rurality_DEFRA_Grouped]
ORDER BY 'Count' DESC, Geography_Rurality_DEFRA_Grouped

SQL：出现次数占仅某些值的百分比

2 个答案: