Inserting into table only if the row does not already exist.

From: "C(dot) Bensend" <benny(at)bennyvision(dot)com>
To: pgsql-sql(at)postgresql(dot)org
Subject: Inserting into table only if the row does not already exist.
Date: 2004-10-15 04:18:21
Message-ID: 56362.63.227.74.41.1097813923.squirrel@63.227.74.41
Views: Raw Message | Whole Thread | Download mbox | Resend email
Thread:
Lists: pgsql-sql


Hey folks,

I am inserting data into a table with a three-column primary key (the
table is only three columns). The rows I'm trying to insert may very
well be duplicates of ones already in the table, so I would like to have
PostgreSQL handle the insert and possible error resulting from dup data.
I can certainly do a SELECT first and then INSERT if it's not a duplicate,
ala:

* Do a SELECT against the three columns
* If there are no rows returned, then do the INSERT

But I thought this would be possible with the following:

INSERT INTO table ( column1, column2, column3 )
SELECT column1, column2, column3
WHERE NOT EXISTS (
SELECT column1, column2, column3 FROM table WHERE
column1 = $column1 AND
column2 = $column2 AND
column3 = $column3 )

.. which gave me 'ERROR: column1 does not exist'. Nuts.

Is this possible to do in one statement? I checked with a DBA friend
(he's an Oracle guy), Google, and the list archives, and either didn't
find anything helpful or simply didn't try the correct search terms. Or
should I be doing this sort of thing in two separate queries?

Thanks for all the help you folks have given me,

Benny

--
"Even if a man chops off your hand with a sword, you still have two nice,
sharp bones to stick in his eyes."
-- .sig on Slashdot

Responses

Browse pgsql-sql by date

  From Date Subject
Next Message Greg Stark 2004-10-15 05:10:50 Re: Inserting into table only if the row does not already exist.
Previous Message ljb 2004-10-15 00:51:32 Re: libpq-fe: PQgetvalue() ?