ASELECT S#,SUM(GRADE)FROM SC WHERE GRADE>=60 GROUP BY S# ORDER BY 2 DESC HAVING COUNT(*)>=4 WHERE C#=“C2” AND GRADE >=(SELECT GRADE FORM SC WHERE C#=“C2”)
BSELECT S# FORM SC WHERE C#=“C2” AND GRADE IN (SELECT GRADE FORM SC WHERE C#=“C2”)
CSELECT S# FORM SC WHERE C#=“C2” AND GRADE NOT IN (SELECT GRADE FORM SC WHERE C#=“C2”)
DSELECT S# FORM SC WHERE C#=“C2” AND GRADE>=ALL (SELECT GRADE FORM SC WHERE C#=“C2”)