SQL 一条SQL语句 统计 各班总人数、男女各总人数 、该班级男女 比例

 

 

1 select count(*) as numOfTotal,
2 sum(case when t.[gender]=\'male\' then 1 else 0 end) as numOfMale , --男生人数
3 sum(case when t.[gender]=\'female\' then 1 else 0 end) numOfFemale, --女生人数
4 sum(case when t.[gender]=\'male\' then 1 else 0 end)*1.0/count(*) as percentOfMale,
5 sum(case when t.[gender]=\'female\' then 1 else 0 end)*1.0/count(*) as perscentOfFemale
6 from
7 (SELECT a.[userid],a.[module],a.[amount],b.[name],b.[gender]
8   FROM [PracticeSQL].[dbo].[module] a inner join [PracticeSQL].[dbo].[user] b
9   on a.[userid]=b.[userid]) t 

 

输出结果：

numOfTotal numOfMale numOfFemale percentOfMale perscentOfFemale
18 14 4 0.777777777777 0.222222222222

 

参考：http://blog.csdn.net/guoxingege/article/details/48054815