1. 查詢數據：select * from xxx;

   例子：

   （1）select id,username,password from t_user;

   （2）select id,username,password,gender from t_user where gender = ‘男‘;

   （3）select id,username,password,gender from t_user where gender is null;

2. 添加數據：insert xxx(id, username) values(xx, "xxx");

   例子：

   insert into t_user(id, username) values(10, "hehehe");

   insert into t_user(id, gender, username, age, password) values(15, ‘男‘, ‘shihu‘, 18, ‘123456‘);

   insert into t_user values(16, ‘benladeng‘, ‘123456‘, ‘拉登‘, ‘nan‘, 18);

3. 修改數據：update tablename set xx=xx,xxx=xx where xxx=xxx and xxx=xxx;

4. 刪除數據：delete from tablename where xx=xxx and xxx = xxx or xxx = xxx;

5. DQL數據查詢語言

   連接查詢

   左外連接

   select

   e.name ename,

   e.gender,

   d.name dname

   from

   t_employee e left outer join t_department d

   on

   e.depart_id = d.id

MySql的基本操作