pg dblink使用查询

目录

一、背景

二、实践

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一、背景

数据库类型：postgres

需要将两个数据库（pg_a/pg_b)下的表在pg里面跨库关联查询。

pg_a数据库的table_a表；pg_b数据库的table_b表。

二、实践

--pg_b库表信息
SELECT *
FROM dblink('dbname=pg_b host=ip user=pg_b_user password=pg_b_pwd port=5432',
'SELECT id, amount FROM table_b') 
AS t(id varchar,amount int8);

--跨库关联
select 
     t1.id,t1.amount,t2.id,t2.amount
from pg_a.table_a t1
left join (
    SELECT *
    FROM dblink('dbname=pg_b host=ip user=pg_b_user password=pg_b_pwd port=5432',
    'SELECT id, amount FROM table_b') 
    AS t(id varchar,amount int8)
) t2
   on t1.id=t2.id
;