选项
A.
USE Xk
GO
SELECT COUNT(*) AS '课程表中选修课程门数'
FROM Course
GO
B.
USE Xk
GO
SELECT SUM(*) AS '课程表中选修课程门数'
FROM Course
GO
C.
USE Xk
GO
SELECT AVG(*) AS '课程表中选修课程门数'
FROM Course
GO
D.
USE Xk
GO
SELECT MIN(*) AS '课程表中选修课程门数'
FROM Course
GO
正确答案：