left join where not null vs. inner join

From: Emi Lu <emilu(at)encs(dot)concordia(dot)ca>
To: PostgreSQL SQL List <pgsql-sql(at)postgresql(dot)org>
Subject: left join where not null vs. inner join
Date: 2009-05-22 20:51:59
Message-ID: 4A17106F.7040302@encs.concordia.ca
Views: Raw Message | Whole Thread | Download mbox | Resend email
Thread:
Lists: pgsql-sql

Two tables, each contains more than hundreds of thousands records. Is
there any efficiency differences between (1) and (2)?

(1) T1 inner join T2 using (c1, c2)

(2) T1 left join T2 using (c1, c2) where c2 is not null

Thanks,
--
Lu Ying

Responses

Browse pgsql-sql by date

  From Date Subject
Next Message Erik Jones 2009-05-22 21:05:32 Re: left join where not null vs. inner join
Previous Message Tom Lane 2009-05-22 18:34:33 Re: help with pg_hba.conf