对于第一个问题，使用下面sql语句查询：

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

第二个问题，比如我想查询eddb库中各个表的数据和索引占用磁盘空间大小，使用下面SQL

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 = 'eddb'
group by TABLE_NAME
order by data_length desc;