Re: Comparing two tables of different database
От | John Zhang |
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Тема | Re: Comparing two tables of different database |
Дата | |
Msg-id | 618950b80905010855y70609c47j187f16967ab0da77@mail.gmail.com обсуждение исходный текст |
Ответ на | Re: Comparing two tables of different database ("Edward W. Rouse" <erouse@comsquared.com>) |
Ответы |
Re: Comparing two tables of different database
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Список | pgsql-sql |
Hi Nicholas,
The query is across database query. dblink is needed for that task.
Hope it helps,
John
Can’t you use this?
select name from database2.sr_1 where name not in (select name from database2.pr_1);
My test database VM isn’t running so I can’t test it, but I seem to remember that that’s how I did it for a few queries of that type. This is assuming the 2 databases are running on the same machine, like the way there is template0 as the default and you add addition databases to the same ‘instance’. If you are talking about 2 different database servers, then I have no idea.
Edward W. Rouse
From: pgsql-sql-owner@postgresql.org [mailto:pgsql-sql-owner@postgresql.org] On Behalf Of Nicholas I
Sent: Thursday, April 30, 2009 6:12 AM
To: Joshua Tolley
Cc: Adam Ruth; Pawel Socha; pgsql-sql@postgresql.org
Subject: Re: [SQL] Comparing two tables of different database
Hi All,
For example,
There are two database. database1 and database 2;
database1 has a table called pr_1 with the columns, id,name and time.
database2 has a table called sr_1 with the_columns id,name and time.
i would like to find out the differences that is, find the names that are not in sr_1 but in pr_1.
we can achieve this by the query,
select name from sr_1 where name not in (select name from pr_1);
the above query will work in case of two tables in the same database.
But the problem is, these two tables are in different database. i did not understand about the dblink.
is there any exaples on dblink. can we do it without using dblink.
-Nicholas I
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