查看某个表的磁盘占用量

select     (data_length+index_length)/1024/1024 M from information_schema.tables where table_schema="db_name" and table_name='table_name';

查看整个数据库的磁盘用量

select     sum((data_length+index_length)/1024/1024) M from information_schema.tables where table_schema="db_name" ;

 

查看整个mysql server 所有数据库的磁盘用量

select     table_schema, sum((data_length+index_length)/1024/1024) M from information_schema.tables where table_schema is not null group by table_schema ;