Re: ADD TO UPDATE LIMIT - Mailing list pgsql-bugs

From Christophe Pettus
Subject Re: ADD TO UPDATE LIMIT
Date
Msg-id 6E2FB117-52FA-44E4-B72D-B043163205A0@thebuild.com
Whole thread Raw
In response to ADD TO UPDATE LIMIT  (Andrey Furs <aefurs93@gmail.com>)
List pgsql-bugs

> On Oct 23, 2020, at 09:36, Andrey Furs <aefurs93@gmail.com> wrote:
>
> Hi there!
> Are you serious !?
> Postgresql not UPDATE LIMIT !?
>
> UPDATE table SET id=100 WHERE id<1000 LIMIT 1;
>
> OMG!

What does that even mean, though?  There's no guarantee as to which row is going to be updated, even if that syntax
worked. LIMIT without an ORDER BY is not statistically random enough to be useful for true randomness, but is not
definedenough to be safe.  What you probably want is: 

    UPDATE t SET id=100 WHERE id = ( SELECT id FROM t ORDER BY id LIMIT 1);

--
-- Christophe Pettus
   xof@thebuild.com




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