SQL跨数据库查询

1. 创建拓展
   create extension dblink;

2. 创建连接
   select dblink_connect(‘myconn’,‘dbname=dbname host=localhost user=username password=123456’);

3. 执行跨库查询并与当前库数据混合查询
   select * from manager.mediafile where personid in (select * from dblink(‘myconn’,‘select id from manager.person where statedm like ‘‘1%’’’) as t(a varchar));//

4. 关闭连接
   select dblink_disconnect(‘myconn’);

5. 关闭拓展
   drop extension dblink;