An example of adding, deleting, and modifying table names in the alter datasheet in MySQL.

Modify the data content in the MySQL database to delete:

[Root@hk ~]#/usr/local/mysql/bin/mysql-uroot-p ' admin ' #进入mysql
Mysql> CREATE DATABASE GBK default Character set GBK collate gbk_chinese_ci; #建立一个名字叫做gbk的数据库
Mysql> Use GBK
mysql> show databases;
+--------------------+
| Database |
+--------------------+
| Information_schema |
| GBK |
+--------------------+
Mysql> Show tables;
Empty Set (0.00 sec)
Mysql> CREATE TABLE Test (#建立一个叫做test的数据表
-> ID int (4) NOT null primary key auto_increment,
-> name char (NOT NULL)
->);
Query OK, 0 rows affected (0.13 sec)

Mysql> Show tables;
+---------------+
| TABLES_IN_GBK |
+---------------+
| Test |
+---------------+
1 row in Set (0.00 sec)
mysql> INSERT INTO Test (Id,name) VALUES (1, ' zy '); #插入部分内容
mysql> INSERT INTO Test (Id,name) VALUES (2, ' Binghe ');
mysql> INSERT INTO Test (Id,name) VALUES (3, ' Zilong ');
mysql> INSERT INTO Test (Id,name) VALUES (4, ' Feng ');
Mysql> select * from test; #检索整个test表
+----+--------+
| ID | name |
+----+--------+
| 1 | Zy |
| 2 | Binghe |
| 3 | Zilong |
| 4 | Feng |
+----+--------+
4 rows in Set (0.00 sec)
[Root@hk ~]#/usr/local/mysql/bin/mysqldump-uroot-p ' admin '-B gbk >/tmp/gbk.sql #备份gbk数据库
mysql> Update Test Set name = ' Zy '; #未定义
Mysql> select * from test; #
+----+------+
| ID | name |
+----+------+
| 1 | Zy |
| 2 | Zy |
| 3 | Zy |
| 4 | Zy |
+----+------+
[Root@hk ~]#/usr/local/mysql/bin/mysql-uroot-p ' admin ' mysql> use GBK
Mysql> select * from test;
+----+--------+
| ID | name |
+----+--------+
| 1 | Zy |
| 2 | Binghe |
| 3 | Zilong |
| 4 | Feng |
+----+--------+
mysql> Update Test Set name = ' Yadianna ' where id = 1;
Mysql> select * from test;
+----+----------+
| ID | name |
+----+----------+
| 1 | Yadianna |
| 2 | Binghe |
| 3 | Zilong |
| 4 | Feng |
+----+----------+
Mysql> Update Test Set id = 999 WHERE name = ' Yadianna ';
Mysql> select * from test;
+-----+----------+
| ID | name |
+-----+----------+
| 2 | Binghe |
| 3 | Zilong |
| 4 | Feng |
| 999 | Yadianna |
+-----+----------+
mysql> Delete from Test where id = 999;
Mysql> select * from test;
+----+--------+
| ID | name |
+----+--------+
| 2 | Binghe |
| 3 | Zilong |
| 4 | Feng |
+----+--------+
mysql> Delete from test where ID <4; #以条件删除
mysql> TRUNCATE TABLE test; #删除all
Mysql> select * from test;
Empty Set (0.00 sec)

On top, modify the table name in the database, add and remove fields from the table.

mysql> Use GBK #进入gbk数据库
mysql> desc test;
+-------+----------+------+-----+---------+----------------+
| Field | Type | Null | Key | Default | Extra |
+-------+----------+------+-----+---------+----------------+
| ID | Int (4) | NO | PRI | NULL | auto_increment |
| name | char (20) |     NO | |                NULL | |
+-------+----------+------+-----+---------+----------------+
Mysql> ALTER TABLE Test add gender char (4); #增加gender
mysql> desc test;
+--------+----------+------+-----+---------+----------------+
| Field | Type | Null | Key | Default | Extra |
+--------+----------+------+-----+---------+----------------+
| ID | Int (4) | NO | PRI | NULL | auto_increment |
| name | char (20) |     NO | |                NULL | |
| Gender | CHAR (4) |     YES | |                NULL | |
+--------+----------+------+-----+---------+----------------+
Mysql> ALTER TABLE test add age int (4) after name;
mysql> desc test;
+--------+----------+------+-----+---------+----------------+
| Field | Type | Null | Key | Default | Extra |
+--------+----------+------+-----+---------+----------------+
| ID | Int (4) | NO | PRI | NULL | auto_increment |
| name | char (20) |     NO | |                NULL | |
| Age | Int (4) |     YES | |                NULL | |
| Gender | CHAR (4) |     YES | |                NULL | |
+--------+----------+------+-----+---------+----------------+
Mysql> Show tables;
+---------------+
| TABLES_IN_GBK |
+---------------+
| Test |
+---------------+
Mysql> Rename table test to Hello;
Mysql> Show tables;
+---------------+
| TABLES_IN_GBK |
+---------------+
| Hello |
+---------------+
mysql> ALTER TABLE Hello Rename to the world;
Mysql> Show tables;
+---------------+
| TABLES_IN_GBK |
+---------------+
| World |
+---------------+
Mysql> ALTER TABLE world drop age;
mysql> DESC World;
+--------+----------+------+-----+---------+----------------+
| Field | Type | Null | Key | Default | Extra |
+--------+----------+------+-----+---------+----------------+
| ID | Int (4) | NO | PRI | NULL | auto_increment |
| name | char (20) |     NO | |                NULL | |
| Gender | CHAR (4) |     YES | |                NULL | |
+--------+----------+------+-----+---------+----------------+
3 Rows in Set (0.00 sec)