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
