SQL实用教程，一个函数构造题

Question

Answer 1

SET ANSI_NULLS ON
GO
SET QUOTED_IDENTIFIER ON
GO
CREATE FUNCTION course_score
(    
    @cno nvarchar(10)
)
RETURNS TABLE 
AS
RETURN 
(
    SELECT * from student s
    left join 选课表 x on s.学生id=x.学生id
    left join 成绩表 c on x.选课id=c.选课id
    where 课程号=@cno
)
GO