Re: How Postgresql Compares... Count(*) and others

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От Bruno Wolff III
Тема Re: How Postgresql Compares... Count(*) and others
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Msg-id 20010722094415.A31190@wolff.to
обсуждение исходный текст
Ответ на How Postgresql Compares... Count(*) and others  (Mark kirkwood <markir@slingshot.co.nz>)
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On Sun, Jul 22, 2001 at 03:06:52PM +1200,
  Mark kirkwood <markir@slingshot.co.nz> wrote:
> Last time I tested this on the big O ( early 8.0.x ) count(*) was always
> fractionally quicker.... there was a body of thought at the time that said
> count(1) or count(<field>) was quicker.... no idea where it came from.

Note that count(<field>) and count(*) are not equivalent. count(<field>)
counts only rows where <field> isn't null.

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