Re: How to use outer join in update - Mailing list pgsql-general

From Ragnar
Subject Re: How to use outer join in update
Date
Msg-id 1165573076.379.70.camel@localhost.localdomain
Whole thread Raw
In response to Re: How to use outer join in update  (Alban Hertroys <alban@magproductions.nl>)
Responses Re: How to use outer join in update  (Ragnar <gnari@hive.is>)
Re: How to use outer join in update  (Tom Lane <tgl@sss.pgh.pa.us>)
List pgsql-general
On fös, 2006-12-08 at 10:09 +0100, Alban Hertroys wrote:
> Andrus wrote:
> > In my current DBMS I can use
> >
> > create table t1 ( f1 int, f2 int );
> > create table t2 ( f3 int, f4 int );
> > update t1 set f1=t2.f3 from t1 left join t2 on  t1.f2=t2.f4
>
> That looks like a self-join on t1 without using an alias for the second
> instance of t1.
>
> I think you meant:
> update t1 set f1=t2.f3 from t2 where f2 = t2.f4

is this not effectively an INNER JOIN ?
the OP needed a LEFT JOIN.

gnari



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