问题 单项选择题

查询选修了课程号为'C2'的学生号和姓名,若用下列SQL的SELECT语句表达时,错误的是( )。

A.SELECT S.S#,SNAME FROM S WHERE S.S#
=(SELECT SC.S# FROM SC WHERE C#='C2')
B.SELECT S.S#,SNAME FROM S,SC
WHERE S.S#==SC.S# AND C#='C2'
C.SELECT S.S#,SNAME FROM S,SC
WHERE S.S#=SC.S# AND C#='C2' ORDER BY S.S#
D.SELECT S.S#,SNAME FROM S WHERE S.S
IN (SELECT SC.S## FROM SC WHERE C#='C2')

答案

参考答案:A

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单项选择题