bk commit - mysqldoc tree (paul:1.2859)

[paul]

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ChangeSet
  1.2859 05/04/13 19:58:02 paul@stripped +1 -0
  manual.texi:
    Add information for ROUND().

  Docs/manual.texi
    1.2694 05/04/13 19:51:50 paul@stripped +36 -1
    Add information for ROUND().

# This is a BitKeeper patch.  What follows are the unified diffs for the
# set of deltas contained in the patch.  The rest of the patch, the part
# that BitKeeper cares about, is below these diffs.
# User:	paul
# Host:	frost.snake.net
# Root:	/Volumes/frost2/MySQL/bk/mysqldoc

--- 1.2693/Docs/manual.texi	2005-04-13 07:17:35 -05:00
+++ 1.2694/Docs/manual.texi	2005-04-13 19:51:50 -05:00
@@ -50082,12 +50082,47 @@
         -> 20
 @end example
 
-Note that the behavior of @code{ROUND()} when the argument
+Before MySQL 5.0.3, the behavior of @code{ROUND()} when the argument
 is halfway between two integers depends on the C library
 implementation.  Different implementations round to the nearest even number,
 always up, always down, or always toward zero.  If you need
 one kind of rounding, you should use a well-defined function
 such as @code{TRUNCATE()} or @code{FLOOR()} instead.
+
+As of MySQL 5.0.3, @code{ROUND()} uses the precision math library.
+for exact-value arguments:
+
+@itemize @bullet
+
+@item
+For exact-value numbers, @code{ROUND()} uses the "round half up" rule:
+A value with a fractional part of .5 or greater is rounded up to
+the next integer if positive or down to the next integer if negative.
+(In other words, it is rounded away from zero.) A value with a
+fractional part less than .5 is rounded down to the next integer
+if positive or up to the next integer if negative.
+
+@item
+For approximate-value numbers, the result depends on the C library.
+On many systems, this means that @code{ROUND()} uses the "round to nearest
+even" rule: A value with any fractional part is rounded to the
+nearest even integer.
+
+@end itemize
+
+The following example shows how rounding differs for exact and
+approximate values:
+
+@example
+mysql> SELECT ROUND(2.5), ROUND(25E-1);
++------------+--------------+
+| ROUND(2.5) | ROUND(25E-1) |
++------------+--------------+
+| 3          |            2 |
++------------+--------------+
+@end example
+
+For more information, see @ref{precision math}.
 
 @c description_for_help_topic SIGN
 @findex SIGN()