Basic operation of MySql database (1)

This article is a record and explanation of some basic operations on the database by MySql

1. Check the version number-MySQL>select version();

1. -SELECT is a standard SQL statement for querying data from the database;
2. VERSION() is a MySQL function that returns the version information of the MySQL database.
3. You need to enter a semicolon (;) after each command to be executed.
4. After the input is complete, press the Enter key, the execution result is as follows:
   

You can also " query " in the visualization tool Navicat

2. View the database-mysql>show databases;

• Use the show databases command to view the database, all databases will be displayed
  

Note: MySQL server has created six databases by default after installation: information_schema,
mysql, performance_ schema, sakila, sys, and worId
.

3. Select the current database-use database name;

• Use the USE command to switch the database used by the SQL statement. The syntax is as follows:

 USE 数据库名;

• E.g:

mysql>use mysql; 

After the USE statement is executed, other SQL statements are executed by default on the specified database.

4. View all tables under the current database-show tables;

Display table information in the database

5. View the table structure-desc table name;

• View the specific table structure, its grammatical structure is as follows:

 describe tablename;

• Example:
  mysql>describe user;
  displays the column information of the user table in the MySQL database
  

6. View storage engines-show engines;

• Storage engine : some rules for database storage, management and query operations
• Use the MySQL command "show engines;" to view
  the storage engines supported by the MySQL service instance .
• Several common storage engines:

1. innoDB storage engine
   • Default storage engine
   • Support foreign keys
   • Support affairs
2. MYISAM
   • Support full-text search
   • Does not support foreign keys
3. MEMERY
   • Memory engine to create tables in memory
   • Fast access