Yep, that is why MySQL for instance has the data type NUMERIC/DECIMAL as opposed to FLOAT and DOUBLE (See: http://dev.mysql.com/doc/refman/5.0/en/numeric-types.html) Also, a lot of programming languages have special datatypes used for storing financial values as they are particularly nasty for rounding errors. Never seen a 0.01 cent difference when Adding a number of items on an invoice programmatically?
Walter On Sun, Sep 5, 2010 at 12:37, Aizuddin a.k.a ak47suk1 <[email protected]> wrote: > Hmmm... > > Tested on my lappy, AMD Turion64 X2, Ubuntu Lucid Lynx 64-bit. > > OpenOffice Calc: > > Input: =161001.165-100000.009-60000.7-1000.456 > Output: 0.00000000000557065504835919 > > Input: =161001.165+(-100000.009-60000.7-1000.456) > Output: 0 > > Input: =((161001.165-100000.009)-60000.7)-1000.456 > Output: 0.00000000000557065504835919 > > MySQL: > > mysql> > mysql> CREATE TABLE `sumtest` ( > -> > -> `numbers` double NOT NULL, > -> > -> `group` varchar(3) NOT NULL DEFAULT 'all' > -> > -> ); > Query OK, 0 rows affected (0.14 sec) > > mysql> > mysql> > mysql> > mysql> INSERT INTO `sumtest` (`numbers`, `group`) VALUES > -> > -> (161001.165, 'all'), > -> > -> (-100000.009, 'all'), > -> > -> (-60000.7, 'all'), > -> > -> (-1000.456, 'all'); > Query OK, 4 rows affected (0.10 sec) > Records: 4 Duplicates: 0 Warnings: 0 > > mysql> > mysql> > mysql> > mysql> SELECT SUM( `numbers` ) > -> > -> FROM `sumtest` > -> > -> WHERE `group` = 'all' > -> > -> GROUP BY `group`; > +----------------------+ > | SUM( `numbers` ) | > +----------------------+ > | 5.57065504835919e-12 | > +----------------------+ > 1 row in set (0.04 sec) > > > 2010/9/5 Raja Iskandar Shah <[email protected]> >> >> cool ;-) >> >> i wonder if the bug is identical across all 32bit and 64bit cpu ? or intel >> treats them differently than amd, than sunsparc, than arm ? >> >> >> On Sun, Sep 5, 2010 at 10:55 AM, Walter Heck - OlinData.com >> <[email protected]> wrote: >>> >>> Usually the programming languages used for those kind of programs have >>> their own datatypes for ultra-high precision floating points. A 32 or >>> 64 bit datatype is not enough for them anyway. They use all kinds of >>> tricks/smart-assing to get around floating point rounding errors. >>> >>> Walter >> >> -- >> Join Open Source Developers Club Malaysia http://www.osdc.my/ >> >> Facebook Fan page >> >> http://www.facebook.com/group.php?gid=98685301577 >> >> http://www.facebook.com/OSDC.my >> >> You received this message because you are subscribed to the Google >> >> Groups "OSDC.my Mailing List" group. >> To post to this group, send email to [email protected] >> To unsubscribe from this group, send email to >> [email protected] >> For more options, visit this group at >> http://groups.google.com/group/osdcmy-list?hl=en > > -- > Join Open Source Developers Club Malaysia http://www.osdc.my/ > > Facebook Fan page > > http://www.facebook.com/group.php?gid=98685301577 > > http://www.facebook.com/OSDC.my > > You received this message because you are subscribed to the Google > > Groups "OSDC.my Mailing List" group. > To post to this group, send email to [email protected] > To unsubscribe from this group, send email to > [email protected] > For more options, visit this group at > http://groups.google.com/group/osdcmy-list?hl=en -- Walter Heck Founder @ OlinData (http://olindata.com) -- Join Open Source Developers Club Malaysia http://www.osdc.my/ Facebook Fan page http://www.facebook.com/group.php?gid=98685301577 http://www.facebook.com/OSDC.my You received this message because you are subscribed to the Google Groups "OSDC.my Mailing List" group. To post to this group, send email to [email protected] To unsubscribe from this group, send email to [email protected] For more options, visit this group at http://groups.google.com/group/osdcmy-list?hl=en
