A guide to basic operational commands for MySQL (MariaDB)

MySQL Basic command operation

1. Login Method:

Mysql-u root-p

2. Show all databases:

show databases;

3. Operation of the specified database (take Information_schema as an example)

Use Information_schema

4. Show all the tables

Show tables;

5. Display the table structure (take the Users table for example)

Discribe tables;

6. Query the size of all databases:

Select Concat (Round (sum (data_length/1024/1024), 2), ' MB ') as data from tables;

7. Query the size of the specified database (take Zabbix as an example):

Select Concat (Round (sum (data_length/1024/1024), 2), ' MB ') as data from tables where table_schema= ' Zabbix ';

8. Query the size of all tables in the specified database (take Zabbix as an example):

SELECT Table_name,data_length+index_length,table_rows,concat (Round (data_length+index_length)/1024/1024,2), ' MB ' ) as Data

From Information_schema.tables WHERE table_schema= ' Zabbix ' ORDER by data_length+index_length desc;

9. Query the size of the specified table in the specified database (in the case of the Zabbix database's history table):

Select Concat (Round (sum (data_length/1024/1024), 2), ' MB ') as data from tables where table_schema= ' Zabbix ' and table_name= ' History ';

A guide to basic operational commands for MySQL (MariaDB)