添加数据

INSERT语句

INSERT INTO table_name

(columnl, column2，)

VALUES(valuel, value2…)

操作实例

SQL> desc userinfo

Name     Type         Nullable Default Comments

-------- ------------ -------- ------- --------

ID       NUMBER(6)    Y

USERNAME VARCHAR2(20) Y

USERPWD  VARCHAR2(20) Y

EMAIL    VARCHAR2(30) Y

REGDATE  DATE         Y

向表中所有字段添加值

SQL> insert into userinfo  values(1,'lewen','123','lewen@163.com',sysdate);

1 row inserted

SQL> select * from userinfo;

ID USERNAME             USERPWD              EMAIL                          REGDATE

------- -------------------- -------------------- ------------------------------ -----------

1 lewen                123                  lewen@163.com                  2020/6/17 2

向表中指定字段添加值

SQL> insert into userinfo(id,username,userpwd) values(2,'fadewalk',123);

1 row inserted

SQL> select username,userpwd from userinfo;

USERNAME             USERPWD

-------------------- --------------------

lewen                123

fadewalk             123

向表中添加默认值

SQL> create table userinfo1(id number(6,0),regdate date default sysdate);

Table created

SQL> select username,userpwd from userinfo;

USERNAME             USERPWD

-------------------- --------------------

lewen                123

fadewalk             123

SQL> create table userinfo1(id number(6,0),regdate date default sysdate);

Table created

SQL> insert into userinfo1(id) values(1);

1 row inserted

SQL> select * from userinfo1;

ID REGDATE

------- -----------

1 2020/6/17 2

SQL> alter table userinfo modify email default 'NULL';

Table altered

SQL> insert into userinfo(id) values(3);

1 row inserted

SQL> select id,email from userinfo;

ID EMAIL

------- ------------------------------

1 lewen@163.com

2

3 NULL

SQL> insert into userinfo(id,email) values(4,'kevin@126.com');

1 row inserted

SQL> select id,email from userinfo;

ID EMAIL

------- ------------------------------

1 lewen@163.com

2

3 NULL

4 kevin@126.com

复制表数据

在建表时复制

CREATE TABLE table_new

AS

SELECT column1,....| *FROM table_old

操作实例

SQL> select id,email from userinfo;

ID EMAIL

------- ------------------------------

1 lewen@163.com

2

3 NULL

4 kevin@126.com

SQL> create table userinfo_new as select * from userinfo;

Table created

SQL> desc userinfo_new

Name     Type         Nullable Default Comments

-------- ------------ -------- ------- --------

ID       NUMBER(6)    Y

USERNAME VARCHAR2(20) Y

USERPWD  VARCHAR2(20) Y

EMAIL    VARCHAR2(30) Y

REGDATE  DATE         Y

SQL> create table userinfo_new_1 as select id,username from userinfo;

Table created

SQL> select * from userinfo_new_1;

ID USERNAME

------- --------------------

1 lewen

2 fadewalk

3

4

在添加时复制

INSERT INTO table_new

[(column1,.....)

SELECT columnl,....| *FROM table_old

操作实例

SQL> insert into userinfo_new select * from userinfo;

4 rows inserted

SQL> select id from userinfo_new;

ID

-------

1

2

3

4

1

2

3

4

8 rows selected

SQL> insert into userinfo_new(id,username) select id,username from userinfo;

4 rows inserted

SQL> select id,username from userinfo_new;

ID USERNAME

------- --------------------

1 lewen

2 fadewalk

3

4

1 lewen

2 fadewalk

3

4

1 lewen

2 fadewalk

3

4

12 rows selected

修改数据

UPDATE语句

UPDATE table_name

SET columnl=value1,.....

[WHERE conditions]

操作实例

SQL> desc userinfo

Name     Type         Nullable Default Comments

-------- ------------ -------- ------- --------

ID       NUMBER(6)    Y

USERNAME VARCHAR2(20) Y

USERPWD  VARCHAR2(20) Y

EMAIL    VARCHAR2(30) Y        'NULL'

REGDATE  DATE         Y

无条件更新

SQL> update userinfo set userpwd='1234';

4 rows updated

SQL> update userinfo set userpwd='1111',email='1111@126.com';

4 rows updated

SQL> select userpwd,email from userinfo;

USERPWD              EMAIL

-------------------- ------------------------------

1111                 1111@126.com

1111                 1111@126.com

1111                 1111@126.com

1111                 1111@126.com

有条件更新

SQL> update userinfo set userpwd='123456' where username='lewen';

1 row updated

SQL> select userpwd,email from userinfo;

USERPWD              EMAIL

-------------------- ------------------------------

123456               1111@126.com

1111                 1111@126.com

1111                 1111@126.com

1111                 1111@126.com

删除数据

DELETE语句

DELETE FROM table_name

[WTHERE conditions]

操作实例

无条件删除

SQL> create table testdel as select * from userinfo;

Table created

SQL> delete from testdel;

4 rows deleted

有条件删除

SQL> delete from userinfo where username='fadewalk';

1 row deleted