Msyql database

# forget your password

Vim / etc/my.cf

Add skip-grant-tables to [mysqld]

Restart Mysql

Now you can go directly to mysql and change the root password.

Execute the following command

USE mysql

UPDATE user SET Password = password ('new password') WHERE User = 'root'; updates the root password in the user table

Flush privileges

Delete the skip-grant-tables added in / etc/my.cf

Restart mysql and you will OK.

Specific operation of mysql

Log in

Mysql-h login host-u user name-p password

two。 Create a database

Create database database name character set gbk

Select the database to use: use database name

You can also choose directly when logging in: mysql-D database name-uroot-p

3. Create a database table

Create table table name (column declaration)

Take the creation of a transcript as an example, with the contents of student number (id), name (name), gender (sex) and grade (grade):

Create table student (

Id int unsigned not null auto_increment primary key

Name char (8) not null

Sex char (4) not null

Grade int unsigned null default "absent"

);

For some longer statements, you can write and save the statements as createtable.sql through any text editor, and execute the script through file redirection at the command prompt.

Mysql-D database name-uroot-p

< createtable.sql 语句解释： 括号内声明了4列内容, id、name、sex、grade为每列的名称, 后面跟的是数据类型描述, 列与列的描述之间用逗号(,)隔开; int指定该列的类型为int（范围为-83888608到83888607），在后面又有unsigned加以修饰，表示该类型为无符号类型，此时该列的取值为0到16777215； not null 表示该列值不能为空，必须填，如果不指定该属性，默认可为空； auto_increment 需在整数列中使用, 其作用是在插入数据时若该列为 NULL, MySQL将自动产生一个比现存值更大的唯一标识符值。在每张表中仅能有一个这样的值且所在列必须为索引列。 primary key 表示该列是表的主键, 本列的值必须唯一, MySQL将自动索引该列。 char(8)表示字符长度为8，tinyint取值范围是-127到128 加上unsigned就是0到255 用show tables；就可以查看记得表了 4.向表中插入数据 insert into student values(值1，值2，值3，值4...) 有时只需要插入部分数据 insert into student (列名1，列名2，列名3） values（值1，值2，值3） 5.查询表中数据 select 列名称 from 表名 [WHERE 查询条件] 例：查询所有人名字 select name from student; 查询所有人学号和姓名 select id,name from student; 查询所有内容 select * from student; 按条件查询 = < >

! = isnot] null in like

Example: query the information of all the girls

Select * from student where sex = 'female'

Inquire about people with scores above 60 points

Select * from student where grade > 60

Inquire about the person surnamed Wang

Select * from student name like'% King%'

Query people whose id is less than 10 and whose score is greater than 60

Select * from stutdent where id60

6. Update the data in the table

Update table name set column name = new value where condition

Example:

Change the score from id 10 to 70

Update student set grade=70 where id=10

Change the name of id from Lu Jiangtao to 10 grade to 60.

Update student set id=10,grade=60 where name=' Lu Jiangtao'

7. Delete data from the table

Delete from table name where condition

Example:

Delete the line of id=2:

Delete from student where id=2

Delete score