試題詳解

34)设有s(学号,姓名,性别)和sc(学号,课程号,成绩)两个表,如下SQL语句检索选 修的每门课程的成绩都高于或等于85分的学生的学号、姓名和性别,正确的是
(A)SELECT学号,姓名,性别FROM s WHERE EXISTS (SELECT* FROM SC WHERE SC.学号=s.学号AND成绩<=85)
(B)SELECT学号,姓名,性别FROM S WHERENOT EXISTS (SELECT * FROM SC WHERE SC.学号=s.学号AND成绩<=85) 、
(C)SELECT学号,姓名,性别FROM S WHEREEXISTS (SELECT * FROM SC WHERE SC.学号=S.学号 AND 成绩>85)
(D)SELECT学号,姓名,性别FROM S WHERENOTEXISTS (SELECT * FROM SC WHERE SC.学号=S.学号AND成绩<85)