使用数据库datatest
https://blog.csdn.net/qq_42759120/article/details/123151453?ops_request_misc=%257B%2522request%255Fid%2522%253A%2522166773828316782412572853%2522%252C%2522scm%2522%253A%252220140713.130102334…%2522%257D&request_id=166773828316782412572853&biz_id=0&utm_medium=distribute.pc_search_result.none-task-blog-2allsobaiduend~default-1-123151453-null-null.142v63control,201v3add_ask,213v1control&utm_term=sql%E5%A4%87%E4%BB%BD%E6%95%B0%E6%8D%AE%E5%BA%93&spm=1018.2226.3001.4187
USE datatest
GO
UPDATE Score
SET score=score+5
FROM Score a, Student b, Class c
WHERE a.studentNo=b.studentNo AND b.classNo=c.classNo
AND c.classno='C0703' AND sex='男'
SELECT *
FROM Score

班级数据
USE datatest
GO
UPDATE Class
SET classNum=sCount
FROM Class a,
( SELECT classNo, count(*) sCount
FROM Student
GROUP BY classNo ) b
WHERE a.classNo=b.classNo
SELECT *
FROM Class
结果

use datatest3
go
CREATE VIEW ViewStudentnation
AS
SELECT *
FROM Student
WHERE nation <> '汉族'

use datatest3
go
SELECT *
FROM ViewStudentnation

use datatest3
go
SELECT *
FROM ViewStudentnation
WHERE nation ='蒙古族'

USE datatest
GO
CREATE VIEW ScoreView
AS
SELECT a.studentNo, a.studentname, b.courseNo,b.courseName, b.creditHour,c.Score
FROM Student a, Course b, Score c
WHERE a.studentNo=c.studentNo AND b.courseNo=c.courseNo AND c.Score>=60
USE datatest
GO
--CREATE VIEW ScoreView
--AS
-- SELECT a.studentNo, a.studentname, b.courseNo,b.courseName, b.creditHour,c.Score
-- FROM Student a, Course b, Score c
-- WHERE a.studentNo=c.studentNo AND b.courseNo=c.courseNo AND c.Score>=60
SELECT *
FROM ScoreView
SELECT studentNo,studentName
FROM ScoreView
WHERE courseName='数据库系统' AND Score >=65
USE datatest
GO
--CREATE VIEW Score60
--AS
-- SELECT a.studentNo, a.studentname, b.courseNo,b.courseName, b.creditHour,c.Score
-- FROM Student a, Course b, Score c
-- WHERE a.studentNo=c.studentNo AND b.courseNo=c.courseNo AND c.Score>=60
DROP VIEW Score60