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RSS订阅原创 SQL经典查询语句(对大小写不敏感)
1）查询被学生选修的课程有几个？（count）select count(Cno)from SC,Cwhere S.Sno = SC.Sno AND Sname = '张三'select count(Cno)from SCwhere Sno in (select Snofrom Swhere Sname='张三')select count(Cno)from SC,Cwhere S.Sno = SC.Sno AND Sname = '张三'select c
2021-12-25 21:10:38
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