Feedback-ID: ia2694551:Fastmail
Date: Thu, 16 May 2024 17:27:18 +0200
From: Alvaro Herrera <alvherre@alvh.no-ip.org>
To: Japin Li <japinli@hotmail.com>
Cc: Etsuro Fujita <etsuro.fujita@gmail.com>, onderkalaci@gmail.com,
	pgsql-bugs@lists.postgresql.org
Subject: Re: BUG #18467: postgres_fdw (deparser) ignores LimitOption
Message-ID: <202405161527.2rs7jfxkxl6m@alvherre.pgsql>
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On 2024-May-16, Japin Li wrote:

> I find that the FETCH FIRST ... ROWS WITH TIES does not support type casting.
> For example:
> 
> postgres=# SELECT * FROM pg_class ORDER BY relname FETCH FIRST 2::bigint ROWS WITH TIES;
> ERROR:  syntax error at or near "::"
> LINE 1: ...ECT * FROM pg_class ORDER BY relname FETCH FIRST 2::bigint R...
>                                                              ^

Why do you need this?  The standard says

<fetch first clause> ::= FETCH { FIRST | NEXT } [ <fetch first quantity> ] { ROW | ROWS } { ONLY | WITH TIES }
<fetch first quantity> ::= <fetch first row count> | <fetch first percentage>
<offset row count> ::= <simple value specification>
<fetch first row count> ::= <simple value specification>

which doesn't seem to leave room for a cast.

I didn't try super extensively, but this works:
  select 1 from pg_class fetch first 281474976710656 rows only;
so the count is already not restricted to be an int32 value.

-- 
Álvaro Herrera         PostgreSQL Developer  —  https://www.EnterpriseDB.com/