mysql统计information_schema表信息
select table_schema, sum(data_length+index_length)/1024/1024 as total_mb,
sum(data_length)/1024/1024 as data_mb, sum(index_length)/1024/1024 as index_mb,
count(*) as tables, curdate() as today from information_schema.tables group by table_schema order by 2 desc;