1、查詢整個mysql數據庫，整個庫的大小；e79fa5e98193e78988e69d8331333431376638單位轉換為MB。
select concat(round(sum(DATA_LENGTH/1024/1024),2),'MB') as data from information_schema.TABLES
2、查詢mysql數據庫，某個庫的大小；
select concat(round(sum(DATA_LENGTH/1024/1024),2),'MB') as data from information_schema.TABLES where table_schema = 'crawl'
2、查詢mysql數據庫，某個庫中某個表的大小；
select concat(round(sum(DATA_LENGTH/1024/1024),2),'MB') as data from information_schema.TABLES where table_schema = 'scrapy' and table_name='test_score'
