sql上机练习5

USE MySchool--查询所有科目的参考信息（某些科目可能还没有被考试过）SELECT J.SubjectName AS 科目名称,R.StudentNo AS 学号,R.StudentResult AS 分数FROM Subject AS JLEFT OUTER JOIN Result AS RON J.SubjectId=R.SubjectIdSELECT J.SubjectName AS 科目名称,R.StudentNo AS 学号,R.StudentResult AS 分数FROM Result AS RRIGHT OUTER JOIN Subject AS JON J.SubjectId=R.SubjectId--查询没有被考过的科目信息。SELECT J.SubjectName AS 科目名称FROM Result AS RRIGHT OUTER JOIN Subject AS JON J.SubjectId=R.SubjectIdWHERE R.StudentResult IS NULL AND R.StudentNo IS NULL--所有年级对应的学生信息（需要考虑某些年级可能还没有学生就读）SELECT G.GradeName AS 年级, S.StudentNo AS 学号,S.StudentName AS 姓名FROM Grade AS GLEFT OUTER JOIN Student AS SON G.GradeId=S.GradeIdSELECT G.GradeName AS 年级, S.StudentNo AS 学号,S.StudentName AS 姓名FROM Student AS SRIGHT OUTER JOIN Grade AS GON G.GradeId=S.GradeId