设有三个关系:S(SNO,SName,Class),C(CNO,CName),SC(SNO,CNO,Score)分别表示学生、课程、选课,那么要得到Class='经统2018-1'的那些选了'数据库'课的学生名单的SQL应是:
A、SELECT S.SName FROM S JOIN SC JOIN C ON S.SNO = SC.SNO AND SC.CNO = C.CNO WHERE S.Class='经统2018-1' AND C.CName = '数据库'
B、SELECT S.SName FROM S JOIN SC ON S.SNO = SC.SNO JOIN C ON SC.CNO = C.CNO WHERE S.Class='经统2018-1' AND C.CName = '数据库'
C、SELECT S.SName FROM S JOIN SC JOIN C WHERE S.Class='经统2018-1' AND C.CName = '数据库' AND S.SNO = SC.SNO AND SC.CNO = C.CNO
D、SELECT S.SName FROM S JOIN C ON S.SNO = C.CNO JOIN SC ON SC.SNO = S.SNO AND SC.CNO = C.CNO WHERE S.Class='经统2018-1' AND C.CName = '数据库'