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help / color / mirror / Atom feedFrom: Erik Brandsberg <[email protected]>
To: szy <[email protected]>
Cc: pgsql-sql <[email protected]>
Subject: Re: Inconsistent results for division and multiplication operations
Date: Mon, 25 Nov 2024 10:53:38 -0500
Message-ID: <CAFcck8EQ3h15-P=Ndt269gE50FDMc=BmWM0iVfUuLbev5HJUbQ@mail.gmail.com> (raw)
In-Reply-To: <[email protected]>
References: <[email protected]>
This is a common issue with using floating point math. You will see the
same issue with many systems. Basically, the order of operations can
trigger very minor differences in results, but if you round the first
result to the same number of significant digits as the input, it would be
identical.
https://learn.microsoft.com/en-us/office/troubleshoot/access/floating-calculations-info
On Mon, Nov 25, 2024 at 10:46 AM szy <[email protected]> wrote:
>
> Hi PostgreSQL community,
>
> I have observed inconsistent results when performing division and
> multiplication operations in PostgreSQL.
>
> postgres=# select 1.003/1.002*5.01;
> ?column?
> --------------------------
> 5.0149999999999999999806
> (1 row)
>
> postgres=# select 1.003*5.01/1.002;
> ?column?
> --------------------
> 5.0150000000000000
> (1 row)
>
> However, the expected result should be consistent for both queries. The
> actual results differ
>
>
> ------------------------------
> szy
> [email protected]
>
> <https://wx.mail.qq.com/home/index?t=readmail_businesscard_midpage&nocheck=true&name=szy&...;
>
>
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To: [email protected]
Cc: [email protected], [email protected], [email protected]
Subject: Re: Inconsistent results for division and multiplication operations
In-Reply-To: <CAFcck8EQ3h15-P=Ndt269gE50FDMc=BmWM0iVfUuLbev5HJUbQ@mail.gmail.com>
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