SELECTSname,Cno,Grade,平均成绩FROMStudentJOINSCONStudent.Sno=SC.SnoJOIN(SELECTSno,AVG(Grade)平均成绩FROMSCGROUPBYSnoHAVINGAVG(Grade)>=80)AONStudent.Sno=A.Sno
