使用外连接查询信息

查询所有科目的考试信息:SELECT SubjectName,StudentNo,StudentResult FROM dbo.Subject AS JLEFT JOIN dbo.Result AS R ON J.SubjectId = R.SubjectId查询从未考试的科目信息SELECT SubjectName,StudentNo,StudentResult FROM dbo.Subject AS JLEFT JOIN dbo.Result AS R ON J.SubjectId = R.SubjectIdWHERE StudentNo IS NULL AND StudentResult IS NULL查询所有年级对应的学生信息SELECT GradeName,StudentNo,StudentName FROM dbo.Grade AS GRIGHT OUTER JOIN dbo.Student AS S ON G.GradeId = S.GradeIdWHERE GradeName = 'Y2'