文档介绍：除法复习
SELECT DISTINCT Sno
FROM SC A
WHERE NOT EXISTS
(SELECT *
FROM SC B
WHERE = ' 22 ' AND
NOT EXISTS
(SELECT *
FROM SC C
WHERE = AND
o=o))
An Introduction to Database System
下面除法语句有什么缺陷?
SELECT DISTINCT Sno
FROM SC A
WHERE NOT EXISTS
(SELECT *
FROM SC B
WHERE = ' 22 ' AND
EXISTS
(SELECT *
FROM SC C
WHERE =)
An Introduction to Database System
与上例的区别?
SELECT DISTINCT Sno
FROM SC A
WHERE NOT EXISTS
(SELECT *
FROM Course B
WHERE NOT EXISTS
(SELECT *
FROM SC C
WHERE = AND
o=o))
An Introduction to Database System
数据库系统概论
An Introduction to Database System
第三章关系数据库标准语言SQL (续2)
An Introduction to Database System
第三章关系数据库标准语言SQL
SQL概述
学生课程数据库
数据定义
数据查询
数据更新
视图
小结
An Introduction to Database System
1. 插入单个元组
语句格式
INSERT
INTO <表名> [(<属性列1>[,<属性列2 >…)]
VALUES (<常量1> [,<常量2>] …)
功能
将新元组插入指定表中。
An Introduction to Database System
插入单个元组(续)
[例1] 将一个新学生记录
(学号:200215128;姓名:陈冬;性别:男;所在系:IS;年龄:18岁)插入到Student表中。
INSERT
INTO Student(sno,sname,ssex,sdept,sage)
VALUES ('200215128', '陈冬', '男','IS',18);
An Introduction to Database System
插入单个元组(续)
[例2] 将学生张成民的信息插入到Student表中
INSERT
INTO Student
VALUES ('200215126', '张成民', '男', 18 ,
'CS');
An Introduction to Database System