ROUND inconsistency
| From: | Lee Howard | Date: | Fri, 13 Apr 2001 02:14:50 +0000 |
| Subject: | ROUND inconsistency | ||
| Groups: | php.general | ||
| Request: | Send a blank email to php-general+get-48387@lists.php.net to get a copy of this message | ||
Using MySQL 3.23.32 on RedHat Linux 7.0...
MySQL's ROUND function rounds 5 up when the preceding digit is odd and down
when the preceding digit is even.
mysql> select round(1.5);
+------------+
| round(1.5) |
+------------+
| 2 |
+------------+
1 row in set (0.00 sec)
mysql> select round(2.5);
+------------+
| round(2.5) |
+------------+
| 2 |
+------------+
1 row in set (0.00 sec)
I think that this is technically the correct behavior, scientifically,
anyway. However, this is not the common "lay-man's" method of rounding,
which is to always round 5 up, as exhibited by PHP-4.0.4pl1...
<? echo round(1.5); ?>
<br>
<? echo round(2.5); ?>
Apache 1.3.14 output for this is:
2
3
This discrepancy causes a difficulty in programming PHP and MySQL together,
for example, because all of the rounding must be done in either PHP or
MySQL but not both partially unless you want conflicting data.
I would like to see MySQL ROUND() syntax expand to be ROUND(X,D,M) where
optional M value indicates the method of rounding, the default being the
current method.
I would also like to see PHP round() syntax expand to be
double round (double val [, int precision] [, char method])
where the optional method value indicates the method of rounding, the
default being the current method.
Thanks.
Lee Howard