• 2022-06-04
    三个表学生表S、课程表C 和学生选课表SC,它们的结构如下S(S#,SN,SEX,AGE,DEPT) C(C#,CN) SC(S#,C#,GRADE) 其中:S#为学号,SN 为姓名,SEX 为性别,AGE 为年龄,DEPT 为系别,C#为课程号,CN 为课程名,GRADE 为成绩。 检索选修课程“C2”的学生中成绩最高的学生的学号,正确的 SELECT 语句是
    A: ELECT S# FORM SC WHERE C#=’C2’ AND GRAD>=(SELECT GRADE FORM SC WHERE C#=’C2’)
    B: SELECT S# FORM SC WHERE C#=’C2’ AND GRADE IN (SELECT GRADE FORM SC WHERE C#=’C2’)
    C: SELECT S# FORM SC WHERE C#=’C2’ AND GRADE NOT IN (SELECT GRADE FORM SC WHERE C#=’C2’)
    D: SELECT S# FORM SC WHERE C#=’C2’ AND GRADE>=ALL (SELECT GRADE FORM SC WHERE C#=’C2’)
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