Re: integer instead of 'double precision'?

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От Henry Drexler
Тема Re: integer instead of 'double precision'?
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Msg-id CAAtgU9T1X_EzBYP4XtWNR9KfJCpE1jjG3KXfxb9WcTHJGL9S=w@mail.gmail.com
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Ответ на Re: integer instead of 'double precision'?  (Tom Lane <tgl@sss.pgh.pa.us>)
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thanks Tom and Guillaume,
That sequencing of casting makes sense - I appreciate the clear explanation.


On Fri, Sep 9, 2011 at 11:12 AM, Tom Lane <tgl@sss.pgh.pa.us> wrote:
Henry Drexler <alonup8tb@gmail.com> writes:
> [ "1/3" yields zero ]

Yeah, it's an integer division.

> I thought perhaps I could cast it as double precision as noted on
> http://www.postgresql.org/docs/8.3/interactive/sql-expressions.html
> though doing the following:
> float8(1/3)

That's casting the result of the division to float, which is way too
late.  You need to cast one or both inputs to non-integer, for instance

       1.0/3
       1/(3::float8)

etc etc.

                       regards, tom lane

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