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RSS订阅原创 SQL语句典型例子
1）查询被学生选修的课程有几个？（count） select count(Cno) from SC,C where S.Sno = SC.Sno AND Sname = ‘张三’ select count(Cno) from SC where Sno in ( select Sno from S where Sname=‘张三’) select count(Cno) from SC,C where S.Sno = SC.Sno AND Sname = ‘张三’ select count(Cno) from
2021-12-25 21:14:28
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