From: Frank Bax <fbax@sympatico.ca>
To: pgsql-sql@postgresql.org
Subject: Re: Non Matching Records in Two Tables
Date: Wed, 08 Feb 2006 16:27:04 -0500
Message-ID: <5.2.1.1.0.20060208162115.023e7ec0@pop6.sympatico.ca> (raw)
In-Reply-To: <1139433024.2044.48.camel@localhost.localdomain>
At 04:10 PM 2/8/06, Ken Hill wrote:
>I need some help with a bit of SQL. I have two tables. I want to find
>records in one table that don't match records in another table based on a
>common column in the two tables. Both tables have a column named 'key100'.
>I was trying something like:
>
>SELECT count(*)
>FROM table1, table2
>WHERE (table1.key100 != table2.key100);
>
>But the query is very slow and I finally just cancel it. Any help is very
>much appreciated.
vacuum analyse table1;
vacuum analyse table2;
select count(*) from table1 full outer join table2 on
table1.key100=table2.key100 where table1.key100 is null or table2.key100 is
null;
If this is also slow, post output of "EXPLAIN ANALYSE SELECT ...."
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To: pgsql-sql@postgresql.org
Cc: fbax@sympatico.ca
Subject: Re: Non Matching Records in Two Tables
In-Reply-To: <5.2.1.1.0.20060208162115.023e7ec0@pop6.sympatico.ca>
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