Re: Count(*) Question

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От Martijn van Oosterhout
Тема Re: Count(*) Question
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Msg-id 20020501100656.B21515@svana.org
обсуждение исходный текст
Ответ на Count(*) Question  ("Peter Darley" <pdarley@kinesis-cem.com>)
Ответы Re: Count(*) Question  ("Joel Burton" <joel@joelburton.com>)
Список pgsql-general
On Tue, Apr 30, 2002 at 04:45:33PM -0700, Peter Darley wrote:
> Friends,
>     I was reading through the Rules section of the online docs, and noticed the
> following note: (* is just an abbreviation for all the attribute names of a
> relation. It is expanded by the parser into the individual attributes, so
> the rule system never sees it.)
>     Does this mean that count(*) may return less than the total number of
> records if all the fields in a record are NULL?

Yes, I beleive so.

>     If this is true, is there a better way to get a count of records?

I think count(1) is the common suggestion.
--
Martijn van Oosterhout   <kleptog@svana.org>   http://svana.org/kleptog/
> Canada, Mexico, and Australia form the Axis of Nations That
> Are Actually Quite Nice But Secretly Have Nasty Thoughts About America

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