1.数据操纵语言
1.1 INSERT
语法格式:
INSERT INTO tablename [(column [,column ...] ) ] VALUES (value [, value... ] )
- 用户需对该表有操作权限
- 可不使用任何column
- value值数值类型需与column相匹配
EX:
SQL> INSERT INTO dept (deptno,dname,loc)
2 VALUES (50,'MARKETING','NEW YORK');
1.2 UPDATE
语法格式:
UPDATE tablename
SET column = value [, column = value, ... ]
[WHERE condition];
EX:
SQL> UPDATE dept
2 SET LOC = 'NEW YORK'
3 WHERE DEPTNO = 60;
也可使用子查询进行更新
UPDATE table
SET column =
(SELECT column
FROM tablename
WHERE condition)
[,
column =
(SELECT column
FROM tablename
WHERE condition)]
[WHERE condition];
EX:
SQL> UPDATE dept
2 set LOC =
3 (SELECT LOC
4 FROM dept
5 WHERE dname = 'MARKETING')
6 WHERE DEPTNO =60;
1.3 DELETE
语法格式:
DELETE [FROM] tablename
[WHERE condition];
- FROM 关键字可选
- WHERE 子句也可选,不使用时,将删除表中所有行(保留表)