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--創(chuàng)建視圖
create view StuClassView as
SELECT s.ID ,s.StuName ,s.StuAge ,s.StuAddress ,s.StuTel ,s.ClassId ,s.StuId,s.StuSex ,e.ClassName,e.ClassInfo,e.ClassFlag
FROM Classes as e left join Students as s on s.ClassId=e.ClassId
Ｓelect sc.ClassName as '班級名稱',count(sc.StuId) as '總人數(shù)' ,sum(case when sc.StuSex='男' then 1 else 0 end) as '男',
sum(case when sc.StuSex='女' then 1 else 0 end) as '女' from StuClassView as sc group by sc.ClassName
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