Re: Select count with offset returns nothing.

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От Scott Marlowe
Тема Re: Select count with offset returns nothing.
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Msg-id CAOR=d=02vPyvG_-DuNvVX3LKZdrKwkR-YVenHde3bkMLUsdrYw@mail.gmail.com
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Ответ на Select count with offset returns nothing.  (Tim Uckun <timuckun@gmail.com>)
Ответы Re: Select count with offset returns nothing.
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On Fri, Aug 5, 2011 at 4:51 AM, Tim Uckun <timuckun@gmail.com> wrote:
> I am using a library which is emitting SQL like this  SELECT COUNT(*)
> FROM batches LIMIT 15 OFFSET 15 the library fails because on postgres
> this query returns nothing (not even zero as a result). Presumably it
> returns some valid value on mysql and other databases.
>
> Other than hacking the library is there anything I can do?
>
> Oddly enough SELECT count(*) FROM batches LIMIT 15 returns the full
> count of the table. Presumably the count has to be done on a subquery
> right?

Since select count(*) will return one row, you're limit / offset are
in the wrong place.  You want something like:

select count(*) from (select * from  batches ordery by something limit
15 offset 15);

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