MySQL Study Notes (1)

Student ID: 2 Name: Li Si Age: 23 Nationality: Shanxi

Student ID: 1 Name: James Age: 22 Local place: Beijing

In the above cases, we found that the space for using paper is wasted.

Table

Student ID	Name	Age	Nationality
1	Zhang San	22	Beijing
2	Li Si	23	Shanxi

The table can only delete rows, but cannot delete columns.

 Server-database-table-row (minimum operation unit: Row)

 

MySQL entry statement:

1. How to connect to the server

Server address (available IP address and domain name): Port (3306)

User Name

Password

Mysql-H localhost-u uername-P passwd

For example, MySQL-H localhost-u root-P

Enter Password: 870210

Or: mysql-uroot-p870210 is hard to write and the password is easy to leak.

-H if this parameter is not set, localhost is used by default.

Exit command: Exit

 

If an error occurs, \ C can be used to complete the event and the statement is like a new statement.

For example, mysql> show databases (the score is missing)

-> \ C

Mysql>

 

2. Check the number of databases on the server.

Show databases;

Command end with a semicolon (;)

 

3. Create a database

Create Database mydatabase;

Create a database named mydatabase

 

4. Select a database

Use mydatabase; (this statement can be left blank)

Mydatabase

 

5. View tables under the database

Show tables;

 

6. delete a database

Drop database mydatabase;

Delete database mydatabase

Note: The database name cannot be modified.

 

7. Create a table

Mysql> Create Table class (

-> Stu int,

-> Name varchar (20 ),

-> Age int,

-> Area varchar (20)

-> );

Note that the last column does not need to be separated by commas (,)

Add another table:

Mysql> Create Table score (

-> Stu int,

-> Name varchar (20 ),

-> Ke varchar (10 ),

-> Fen int

-> );

 

8. Modify the table name

Syntax: rename table oldname to newname

For example, rename table score to newscore;

 

9. Delete table name

Drop table newscore;

Delete table newscore

 

10. view the table structure

Desc class;

View the (description) class Table Structure

 

Create a comment table:

Create Table MSG (

Id int,

Title varchar (60 ),

Name varchar (10 ),

Content varchar (1, 1000)

);