整理數據庫的時候相關數據統計查詢

首先查詢所有數據庫佔用磁盤空間大小的SQL語句如下：

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;

然後是查詢單個數據庫裏面各個表所佔磁盤空間大小包括其索引的大小，SQL語句如下：

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 = `dbname` 
group by TABLE_NAME 
order by data_length desc;

mysql 查看數據庫中所有表的記錄數

use information_schema; 
select table_name,table_rows from tables 
where TABLE_SCHEMA = 'dbname' 
order by table_rows desc;

導出數據庫文件，並忽略某張表

/usr/bin/mysqldump --set-gtid-purged=OFF -h127.0.0.1 -uroot -p123456 dbname --ignore-table=dbname.tb1
--ignore-table=dbname.tb2 > ./db_files/dsp.sql