Re: How to get only the non-matching entries from an outer join
From: Heinz Huber <hhuber_at_racon-linz.at>
Date: Wed, 27 Nov 2002 11:25:48 +0100
Message-ID: <3de49dae$0$21580$91cee783_at_newsreader01.highway.telekom.at>
>
>
> No, the WHERE clause is applied AFTER an Outer Join, that's why the result
> set is correct.
Date: Wed, 27 Nov 2002 11:25:48 +0100
Message-ID: <3de49dae$0$21580$91cee783_at_newsreader01.highway.telekom.at>
Dieter Nöth wrote:
> Heinz Huber wrote:
>
>>> SELECT T2.FK, T1.PK >>> FROM T2 >>> LEFT JOIN T1 ON T2.FK = T1.PK >>> WHERE (T1.PK Is Null); >> >>AFAIK, this will give you all rows from T2 without any data from T1. >>The where clause is applied BEFORE the outer join. Therefore all rows >>from T1 are filtered out since the PK cannot be NULL.
>
>
> No, the WHERE clause is applied AFTER an Outer Join, that's why the result
> set is correct.
Heinz Received on Wed Nov 27 2002 - 11:25:48 CET