关于SQL求助,请大家帮忙!

select STUDENT_NO,STUDENT_NAME,STUDENT_SEX,SUBJECT_NO,SUBJECT_NAME from TEST_STUDENT,TEST_SUBJECT
select STUDENT_NO,STUDENT_NAME,STUDENT_SEX from TEST_STUDENT,TEST_SUBJECT where TEST_STUDENT.STUDENT_NO=TEST_SUBJECT_NO
select STUDENT_NO,STUDENT_NAME,SUBJECT_NAME,avg(SUBJECT_SCORE),sum(SUBJECT_SCROE) from TEST_STUDENT,TEST_SUBJECT,TEST_GRADE_INFO where TEST_STUDENT.STUDENT_NO=TEST_SUBJECT.SUBJECT_NO and TEST_GRADE_INFO.STUDENT_NO=TEST_STUDENT.STUDENT_NO and
不知道对不对.你试试吧