MySQL获取分组后的TopN条数据

表结构 mysql> desc dce_his_cs_m_jyhqsj; +---------+---------------+------+-----+---------+----------------+ | Field | Type | Null | Key | Default | Extra | +---------+---------------+------+-----+---------+----------------+ | QSJDATE | varchar(20) | YES | | NULL

iptables简单使用例子

保存 sudo iptables-save > iptables.rule 还原 sudo iptables-restore < iptables.rule 持久化 sudo apt-get install iptables-persistent 删除某条规则 sudo iptables -L --line-numbers 然

PostgreSQL9.6中使用mysql_fdw

安装 mysql_fdw SELECT * from pg_available_extensions where name like '%fdw%'; name | default_version | installed_version | comment --------------+-----------------+-------------------+---------------------------------------------------- file_fdw | 1.0 | [null] | foreign-data wrapper for flat file