Re: Inconsistent results for division and multiplication operations - Mailing list pgsql-sql

From Erik Brandsberg
Subject Re: Inconsistent results for division and multiplication operations
Date
Msg-id CAFcck8EQ3h15-P=Ndt269gE50FDMc=BmWM0iVfUuLbev5HJUbQ@mail.gmail.com
Whole thread Raw
In response to Inconsistent results for division and multiplication operations  ("szy" <598546998@qq.com>)
Responses 回复: Inconsistent results for division and multiplication operations
Re: Inconsistent results for division and multiplication operations
Re: Inconsistent results for division and multiplication operations
List pgsql-sql
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 <598546998@qq.com> 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



 

pgsql-sql by date:

Previous
From: "szy"
Date:
Subject: Inconsistent results for division and multiplication operations
Next
From: "szy"
Date:
Subject: 回复: Inconsistent results for division and multiplication operations