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From:Doug Thompson Date:April 12 2003 8:26pm
Subject:Re: rounding/truncation of decimal fields
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On Sat, 12 Apr 2003 10:41:01 -0400 (EDT), Matt Loschert wrote:

>Interesting.  I had never seen this page of the manual before.  However,
>you appear to be correct.  I don't see an applicable reference there
>either.
>
>I think I am going to re-post my message to the bugs list since no one has
>shown me yet that this is definitely expected behavior.
>

Huh?!?

Here are the first two sentences from Appendix A.5.7.

<quote>
floating-point numbers cause confusion sometimes, because these numbers are not stored as
exact values inside computer architecture. What one can see on the screen usually is not
the exact value of the number. 

Field types FLOAT, DOUBLE and DECIMAL are such. 
<end quote>

Seems to me that's rather explicit that what you are seeing is expected behavior.


>Thanks,
>
>- Matt
>
>On Fri, 11 Apr 2003, Doug Thompson wrote:
>
>> I don't see this reference mentioned anywhere in this thread:
>>
>> http://www.mysql.com/doc/en/Problems_with_float.html
>>
>> Doug
>>
>>
>> On Fri, 11 Apr 2003 15:36:45 -0400 (EDT), Matt Loschert wrote:
>>
>> >Exactly the point.  I am not saying it is wrong.  I am just wondering if
>> >it is supposed to operate this way.  I would assume (possibly incorrectly)
>> >that a number supplied as a string would be transformed to numerical form
>> >by MySQL, then inserted into the database (and consequently rounded or
>> >truncated, I don't care which, I just want consistency) as is done when
>> >you insert a number as a number.
>> >
>> >On Fri, 11 Apr 2003, gerald_clark wrote:
>> >
>> >> Well, in one case he supplied a string, not a number.
>> >> It most likely was promoted to a float before is was saved.
>> >>
>> >> Jones, Clifton R [CC] wrote:
>> >>
>> >> >No, I think he was surprised to find mySQL rounded two identical
> values
>> >> >*differently*.. please read his posting for the results....
>> >> >
>> >> >
>> >> >
>> >> >
>> >> >>-----Original Message-----
>> >> >>From: gerald_clark [mailto:gerald_clark@stripped]
>> >> >>Sent: Friday, April 11, 2003 9:33 AM
>> >> >>To: Matt Loschert
>> >> >>Cc: mysql@stripped
>> >> >>Subject: Re: rounding/truncation of decimal fields
>> >> >>
>> >> >>
>> >> >>Why do you find this surprising?
>> >> >>You defined the field to have 2 deciimal places..
>> >> >>
>> >> >>Matt Loschert wrote:
>> >> >>
>> >> >>
>> >> >>
>> >> >>>I have quick question about rounding and/or truncation of a
>> >> >>>
>> >> >>>
>> >> >>decimal table
>> >> >>
>> >> >>
>> >> >>>field.  I ran into this unexpectedly and found it
> surprising.
>> >> >>>
>> >> >>>Given the following input:
>> >> >>>
>> >> >>>
>> >> >>> DROP TABLE IF EXISTS test1;
>> >> >>> CREATE TABLE test1 (id tinyint, truncated decimal(12,2));
>> >> >>> INSERT INTO test1 VALUES (1, '0.004');
>> >> >>> INSERT INTO test1 VALUES (2,  0.004 );
>> >> >>> INSERT INTO test1 VALUES (3, '0.005');
>> >> >>> INSERT INTO test1 VALUES (4,  0.005 );
>> >> >>> SELECT * FROM test1;
>> >> >>> SELECT VERSION();
>> >
>> >- Matt
>> >
>> >--
>> >Matt Loschert - Software Engineer       | email: loschert@stripped    |
>> >ServInt Internet Services               | web:   http://www.servint.net/ |
>> >McLean, Virginia USA                    | phone: (703) 847-1381          |
>
>-- 
>MySQL General Mailing List
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>


Thread
rounding/truncation of decimal fieldsMatt Loschert10 Apr
  • Re: rounding/truncation of decimal fieldsgerald_clark11 Apr
RE: rounding/truncation of decimal fieldsClifton R [CC] Jones11 Apr
  • Re: rounding/truncation of decimal fieldsgerald_clark11 Apr
    • Re: rounding/truncation of decimal fieldsMatt Loschert11 Apr
      • Re: rounding/truncation of decimal fieldsDoug Thompson11 Apr
        • Re: rounding/truncation of decimal fieldsMatt Loschert12 Apr
          • Re: rounding/truncation of decimal fieldsDoug Thompson12 Apr
            • More on enumMartin Gainty12 Apr
            • Re: rounding/truncation of decimal fieldsMatt Loschert13 Apr
              • Re: rounding/truncation of decimal fieldsDoug Thompson13 Apr
              • Re: rounding/truncation of decimal fieldsDan Nelson13 Apr
                • Re: rounding/truncation of decimal fieldsMatt Loschert14 Apr
Re: rounding/truncation of decimal fieldsMoon79611 Apr