Re: Creating Index

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От Stephan Szabo
Тема Re: Creating Index
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Msg-id 20031001110830.O40704@megazone.bigpanda.com
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Ответ на Re: Creating Index  ("CN" <cnliou9@fastmail.fm>)
Ответы Re: Creating Index  ("CN" <cnliou9@fastmail.fm>)
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On Wed, 1 Oct 2003, CN wrote:

> Peter, Thanks a lot!
>
> > Unqualified count() cannot use an index because it has to visit all the
> > rows in the table.
>
> It is only for my test. In my real practice, queries like
> "SELECT * FROM view1 WHERE year = 2003 AND month BETWEEN 10 AND 12"
> will be performed.

You do realize that extract returns a double precision value not an
integer, and it's probably not going to be willing to push clauses down
through the union where the types are different .



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