Re: To Postgres Devs : Wouldn't changing the select limit - Mailing list pgsql-general

From Bruce Momjian
Subject Re: To Postgres Devs : Wouldn't changing the select limit
Date
Msg-id 200110201642.f9KGgOL16522@candle.pha.pa.us
Whole thread Raw
In response to Re: To Postgres Devs : Wouldn't changing the select limit  (Tom Lane <tgl@sss.pgh.pa.us>)
List pgsql-general
> Bruce Momjian <pgman@candle.pha.pa.us> writes:
> >> If you're going to do that, *please* suggest the *correct* substitution.
> >> AFAICT, our version of LIMIT m,n transposes to OFFSET m LIMIT n; but
> >> your message suggests the opposite.
>
> > Remember, the 7.1 code was:
>
> > ! select_limit: LIMIT select_limit_value ',' select_offset_value
> > !                       { $$ = makeList2($4, $2); }
>
> > This was changed a few weeks ago to match MySQL, and only today removed.
>
> Wups, you're right, I was looking at the cvs-tip code not 7.1.
> What was that about the order not being easy to remember? :-(

Confusing syntax proven!

> > However, our new message suggests the old PostgreSQL syntax, not the
> > MySQL syntax.  Optimally we should ship with this ordering for 7.2 and
> > reverse it for 7.3 or 7.4.
>
> Actually, it seems that the message should point out *both* the
> old-Postgres and the MySQL translations.  One camp or the other
> is going to get burnt otherwise.  Maybe:
>
> ERROR:  LIMIT #,# syntax no longer supported.  Use LIMIT # OFFSET #.
>     If translating pre-7.2 Postgres: LIMIT m,n => LIMIT m OFFSET n
>     If translating MySQL: LIMIT m,n => OFFSET m LIMIT n

I opted for a more generic message which makes clear the person it is
not a cut-and-past error message:

    test=> select * from pg_class LIMIT 1,1;
    ERROR:  LIMIT #,# syntax no longer supported.
            Use separate LIMIT and OFFSET clauses.

That should take care of it in a flexible way.

--
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