MySQL的链接，查看数据库，使用数据库，查看表
mysql> show databases;
+--------------------+
| Database |
+--------------------+
| information_schema |
| mysql |
| performance_schema |
| qq |
| test |
+--------------------+
5 rows in set (0.06 sec) mysql> use qq;
Database changed
mysql> desc qq;
ERROR 1146 (42S02): Table 'qq.qq' doesn't exist
mysql> desc table;
ERROR 1064 (42000): You have an error in your SQL syntax; check the manual that corresponds to your MySQL server version for the right syntax to use near 'table' at line 1
mysql> set name gbk;
ERROR 1193 (HY000): Unknown system variable 'name'
mysql> set names gbk;
Query OK, 0 rows affected (0.00 sec) mysql> show tables;
+--------------+
| Tables_in_qq |
+--------------+
| stu |
+--------------+
1 row in set (0.01 sec) mysql> desc stu;
+-------+------------+------+-----+---------+-------+
| Field | Type | Null | Key | Default | Extra |
+-------+------------+------+-----+---------+-------+
| id | int(11) | YES | | NULL | |
| name | varchar(4) | YES | | NULL | |
+-------+------------+------+-----+---------+-------+
2 rows in set (0.02 sec) mysql> select * from stu;
+------+------+
| id | name |
+------+------+
| 1 | lisi |
| NULL | 李四 |
+------+------+
2 rows in set (0.01 sec) mysql> insert into stu values
-> (2,'zhangsan');
ERROR 1406 (22001): Data too long for column 'name' at row 1
mysql> insert into stu values
-> (2,'zhangsan')
-> (3,'zhan');
ERROR 1064 (42000): You have an error in your SQL syntax; check the manual that corresponds to your MySQL server version for the right syntax to use near '(3,'zhan')' at line 3
mysql> insert into stu values
-> (2,'zhan');
Query OK, 1 row affected (0.00 sec) mysql> show tables;
+--------------+
| Tables_in_qq |
+--------------+
| stu |
+--------------+
1 row in set (0.00 sec) mysql> select (name) from stu;
+------+
| name |
+------+
| lisi |
| 李四 |
| zhan |
+------+
3 rows in set (0.00 sec) mysql> delete form where id=3;
ERROR 1064 (42000): You have an error in your SQL syntax; check the manual that corresponds to your MySQL server version for the right syntax to use near 'where id=3' at line 1
mysql> delete from stu where id=3;
Query OK, 0 rows affected (0.02 sec) mysql> select (name) from stu;
+------+
| name |
+------+
| lisi |
| 李四 |
| zhan |
+------+
3 rows in set (0.00 sec) mysql> select * from stu;
+------+------+
| id | name |
+------+------+
| 1 | lisi |
| NULL | 李四 |
| 2 | zhan |
+------+------+
3 rows in set (0.00 sec) mysql> delete from stu where id\
-> id=null;
ERROR 1064 (42000): You have an error in your SQL syntax; check the manual that corresponds to your MySQL server version for the right syntax to use near 'id=null' at line 2
mysql> delete from stu where id=null;
Query OK, 0 rows affected (0.00 sec) mysql> delete from stu where id=NULL;
Query OK, 0 rows affected (0.00 sec) mysql> delete from stu where id='';
Query OK, 0 rows affected (0.00 sec) mysql> delete from stu where id=2;
Query OK, 1 row affected (0.00 sec) mysql> select * from stu;
+------+------+
| id | name |
+------+------+
| 1 | lisi |
| NULL | 李四 |
+------+------+
2 rows in set (0.00 sec) mysql> insert into classs
-> /c
-> \c
mysql>
mysql> insert into class(
-> \c
mysql> create table class(
-> id int primary key auto_increment,
-> sname varchar(10) not null default '',
-> gender char(1) not null default '',
-> company varchar(20) not null default '',
-> salary decimal (6,2) not null default 0.00
-> )engine myisam charset utf8;
Query OK, 0 rows affected (0.08 sec) mysql> desc class;
+---------+--------------+------+-----+---------+----------------+
| Field | Type | Null | Key | Default | Extra |
+---------+--------------+------+-----+---------+----------------+
| id | int(11) | NO | PRI | NULL | auto_increment |
| sname | varchar(10) | NO | | | |
| gender | char(1) | NO | | | |
| company | varchar(20) | NO | | | |
| salary | decimal(6,2) | NO | | 0.00 | |
+---------+--------------+------+-----+---------+----------------+
5 rows in set (0.00 sec) mysql> insert into class
-> values
-> (1,'张三','男','百度',7000);
Query OK, 1 row affected (0.03 sec) mysql> show table from class;
ERROR 1064 (42000): You have an error in your SQL syntax; check the manual that corresponds to your MySQL server version for the right syntax to use near 'from class' at line 1
mysql> select * form class;
ERROR 1064 (42000): You have an error in your SQL syntax; check the manual that corresponds to your MySQL server version for the right syntax to use near 'form class' at line 1
mysql> select * from class;
+----+-------+--------+---------+---------+
| id | sname | gender | company | salary |
+----+-------+--------+---------+---------+
| 1 | 张三 | 男 | 百度 | 7000.00 |
+----+-------+--------+---------+---------+
1 row in set (0.01 sec) mysql> insert into
-> (name,gender,company)
-> values
-> ('lisi','男','ibm');
ERROR 1064 (42000): You have an error in your SQL syntax; check the manual that corresponds to your MySQL server version for the right syntax to use near '(name,gender,company)
values
('lisi','男','ibm')' at line 2
mysql> insert into class
-> (name,gender,company)
-> values
-> ('lisi','男','ibm')
-> ;
ERROR 1054 (42S22): Unknown column 'name' in 'field list'
mysql> insert into class
-> (sname,gender,company)
-> values
-> ('lizi','男','ibm');
Query OK, 1 row affected (0.00 sec) mysql> select * from class;
+----+-------+--------+---------+---------+
| id | sname | gender | company | salary |
+----+-------+--------+---------+---------+
| 1 | 张三 | 男 | 百度 | 7000.00 |
| 2 | lizi | 男 | ibm | 0.00 |
+----+-------+--------+---------+---------+
2 rows in set (0.00 sec) mysql> select * from class where company;
Empty set, 2 warnings (0.00 sec) mysql> select * from class;
+----+-------+--------+---------+---------+
| id | sname | gender | company | salary |
+----+-------+--------+---------+---------+
| 1 | 张三 | 男 | 百度 | 7000.00 |
| 2 | lizi | 男 | ibm | 0.00 |
+----+-------+--------+---------+---------+
2 rows in set (0.00 sec) mysql> select company from class;
+---------+
| company |
+---------+
| 百度 |
| ibm |
+---------+
2 rows in set (0.00 sec) mysql> select * from class where id=2;
+----+-------+--------+---------+--------+
| id | sname | gender | company | salary |
+----+-------+--------+---------+--------+
| 2 | lizi | 男 | ibm | 0.00 |
+----+-------+--------+---------+--------+
1 row in set (0.00 sec) mysql> #改，改哪张表，哪几列， 哪几行，改成什么值。
mysql> update class
-> set salary=7800
-> where id=2;
Query OK, 1 row affected (0.01 sec)
Rows matched: 1 Changed: 1 Warnings: 0 mysql> select * from class;
+----+-------+--------+---------+---------+
| id | sname | gender | company | salary |
+----+-------+--------+---------+---------+
| 1 | 张三 | 男 | 百度 | 7000.00 |
| 2 | lizi | 男 | ibm | 7800.00 |
+----+-------+--------+---------+---------+
2 rows in set (0.02 sec)