问题详情

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，哪一个是错误的？______。
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 BYS.S#
D．SELECT S.S#,SNAME FROM S WHERE S.S# IN(SELECT SC.S# FROM SC WHERE C#="C2")请帮忙给出正确答案和分析，谢谢！