问题详情

查询选修了课程号为"C2"的学号和姓名，若用下列SQL的SELECT语句表达时，哪一个是不正确的？ ()
A．SELECTS. S#，SNAMEFROMS WHERE S. S#=(SELECTSC)S# FROMSC WHERE C#="C2"
B．SELECTS．S#，SNAMEFROMS，SC WHERES．S#=SC.S# AND C#="C2"
C．SELECTS．S#，SNAME FROM S，SC WHERES．S#=SC.S# AND C#="C2"ORDER BY S.S#
D．SELECTS．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！