A.SELECT s.学号,姓名,课程名,成绩 FROM student s,score sc,course c WHERE s.学号=sc.学号,sc.课程号=c.课程号,院系=’计算机系’ B.SELECT学号,姓名,课程名,成绩 FROM student s,score sc,course c WHERE s.学号=sc.学号AND sc.课程号=c.课程号AND院系=’计算机系’ C.SELECT s.学号,姓名,课程名,成绩 FROM(student s JOIN score se ON s.学号=sc.学号) JOIN course c ON sc.课程号=c.课程号 WHERE院系=’计算机系’ D.SELECT学号,姓名,课程名,成绩 FROM(student s JOIN score sc ON s.学号=sc.学号) JOIN course c ON sc.课程号=c.课程号 WHERE院系=’计算机系’