1、指定schema 数据库

use information_schema;

2、查询所有数据的大小

select concat(round(sum(DATA_LENGTH/1024/1024),2),'MB') as data from TABLES;

3、查看指定数据库的大小(如school)

select concat(round(sum(DATA_LENGTH/1024/1024),2),'MB') as data from TABLES where table_schema='school';

4、查看指定数据库的表的大小(如数据库school中的user表)

select concat(round(sum(DATA_LENGTH/1024/1024),2),'MB') as data from TABLES where table_schema='school' and table_name='user';