MySQL所有数据库空间量计算：

select concat(truncate(sum(data_length)/1024/1024,2),' MB') as data_size from information_schema.tables;

按照数据库分组计算：

select TABLE_NAME, concat(truncate(data_length/1024/1024,2),' MB') as data_size, concat(truncate(index_length/1024/1024,2),' MB') as index_size from information_schema.tables where TABLE_SCHEMA = 'TestDB' group by TABLE_NAME order by data_length desc;