mysql> use information_schema;
Database changed
mysql> select concat(round(sum(DATA_LENGTH/1024/1024),2),'MB') as data from TABLES
mysql> select concat(round(sum(DATA_LENGTH/1024/1024),2),'MB') as data from TABLES where table_schema='xxxxx'
select concat(round(sum(data_length/1024/1024),2),'MB') as data from tables where table_schema='home' and table_name='members';