Bug #9060 Precision math: FORMAT returns incorrect result,
Submitted: 8 Mar 2005 23:47 Modified: 23 May 2005 1:55
Reporter: Petr Chloupek
Status: Closed
Category:Server Severity:S3 (Non-critical)
Version:4.0.23 OS:Linux (Debian)
Assigned to: Alexey Botchkov Target Version:

[8 Mar 2005 23:47] Petr Chloupek 
Description:
Precision math: FORMAT returns incorrect result, probably simillar to #8459

mysql> select format(4.55,1),format(4.551,1);
+----------------+-----------------+
| format(4.55,1) | format(4.551,1) |
+----------------+-----------------+
| 4.5            | 4.6             |
+----------------+-----------------+
1 row in set (0.00 sec)

At least very odd math, what is annoying when you are counting money. Maybe fixed
somewhere in CVS, but I haven't found it in 4.0.24 change log.

How to repeat:
select format(4.55,1),format(4.551,1); in command line 'mysql' client.

Suggested fix:
fix rounding or explain in documentation if this is a feature. Just "rounding" is
misleading.
[16 Mar 2005 9:01] Alexey Botchkov 
First i should say that there's no Precision Math in 4.0 (neither in 4.1)
It only appeared in 5.0 version
[16 Mar 2005 20:40] Bugs System 
A patch for this bug has been committed. After review, it may
be pushed to the relevant source trees for release in the next
version. You can access the patch from:

  http://lists.mysql.com/internals/23106
[18 Mar 2005 9:23] Alexey Botchkov 
bk commit - 4.0 tree (hf:1.2086) BUG#9060
[19 May 2005 14:49] Michael Widenius 
This patch should only be pushed in 5.0 as 4.0 (and 4.1) doesn't have precision math and
4.55 is not an exact number and may thus be rounded either up or down.
[19 May 2005 22:13] Ramil Kalimullin 
fixed in 5.0.6
[23 May 2005 1:55] Paul DuBois 
Note in 5.0.6 changelog.