1：使用以下命令查詢指定資料庫容量大小：

where table_schema='mysql'    #mysql是資料庫名稱，將mysql修改自己想要查詢的資料庫即可。

select
table_schema as '資料庫',
sum(table_rows) as '記錄數',
sum(truncate(data_length/1024/1024, 2)) as '資料容量(MB)',
sum(truncate(index_length/1024/1024, 2)) as '索引容量(MB)'
from information_schema.tables
where table_schema='mysql';

2：查詢資料庫中所有表的大小及資訊：

select
table_schema as '資料庫',
table_name as '表名',
table_rows as '記錄數',
truncate(data_length/1024/1024, 2) as '資料容量(MB)',
truncate(index_length/1024/1024, 2) as '索引容量(MB)'
from information_schema.tables
where table_schema='mysql'
order by data_length desc, index_length desc;

3：查詢所有資料庫大小及資訊：

select
table_schema as '資料庫',
sum(table_rows) as '記錄數',
sum(truncate(data_length/1024/1024, 2)) as '資料容量(MB)',
sum(truncate(index_length/1024/1024, 2)) as '索引容量(MB)'
from information_schema.tables
group by table_schema
order by sum(data_length) desc, sum(index_length) desc;