manual.texi minor change log fixes

manual.texi	fix age calculations in the tutorial section to
manual.texi	determine age in integer years and to account for
manual.texi	relative order of dates within calendar year.

1 files changed, 89 insertions, 73 deletions

diff --git a/Docs/manual.texi b/Docs/manual.texi
index c4618c2ada7..286926e102e 100644
--- a/Docs/manual.texi
+++ b/Docs/manual.texi
@@ -13170,75 +13170,89 @@ MySQL provides several functions that you can use to perform
 calculations on dates, for example, to calculate ages or extract
 parts of dates.
 
-To determine how many years old each of your pets is, compute age as the
-difference between the birth date and the current date.  Do this by
-converting the two dates to days, take the difference, and divide by 365 (the
-number of days in a year):
-
-@example
-mysql> SELECT name, (TO_DAYS(NOW())-TO_DAYS(birth))/365 FROM pet;
-+----------+-------------------------------------+
-| name     | (TO_DAYS(NOW())-TO_DAYS(birth))/365 |
-+----------+-------------------------------------+
-| Fluffy   |                                6.15 |
-| Claws    |                                5.04 |
-| Buffy    |                                9.88 |
-| Fang     |                                8.59 |
-| Bowser   |                                9.58 |
-| Chirpy   |                                0.55 |
-| Whistler |                                1.30 |
-| Slim     |                                2.92 |
-| Puffball |                                0.00 |
-+----------+-------------------------------------+
-@end example
-
-Although the query works, there are some things about it that could be
-improved.  First, the result could be scanned more easily if the rows were
-presented in some order.  Second, the heading for the age column isn't very
+To determine how many years old each of your pets is, compute the
+difference in the year part of the current date and the birth date, then
+subtract one if the current date occurs earlier in the calendar year than
+the birth date.  The following query shows, for each pet, the birth date,
+the current date, and the age in years.
+
+@example
+mysql> SELECT name, birth, CURRENT_DATE,
+    -> (YEAR(CURRENT_DATE)-YEAR(birth))
+    -> - (RIGHT(CURRENT_DATE,5)<RIGHT(birth,5))
+    -> AS age
+    -> FROM pet;
++----------+------------+--------------+------+
+| name     | birth      | CURRENT_DATE | age  |
++----------+------------+--------------+------+
+| Fluffy   | 1993-02-04 | 2001-08-29   |    8 |
+| Claws    | 1994-03-17 | 2001-08-29   |    7 |
+| Buffy    | 1989-05-13 | 2001-08-29   |   12 |
+| Fang     | 1990-08-27 | 2001-08-29   |   11 |
+| Bowser   | 1989-08-31 | 2001-08-29   |   11 |
+| Chirpy   | 1998-09-11 | 2001-08-29   |    2 |
+| Whistler | 1997-12-09 | 2001-08-29   |    3 |
+| Slim     | 1996-04-29 | 2001-08-29   |    5 |
+| Puffball | 1999-03-30 | 2001-08-29   |    2 |
++----------+------------+--------------+------+
+@end example
+
+Here, @code{YEAR()} pulls out the year part of a date and @code{RIGHT()}
+pulls off the rightmost five characters that represent the @code{MM-DD}
+(calendar year) part of the date.  The part of the expression that
+compares the @code{MM-DD} values evaluates to 1 or 0, which adjusts the
+year difference down a year if @code{CURRENT_DATE} occurs earlier in
+the year than @code{birth}.  The full expression is somewhat ungainly,
+so an alias (@code{age}) is used to make the output column label more
 meaningful.
 
-The first problem can be handled by adding an @code{ORDER BY name} clause to
-sort the output by name.  To deal with the column heading, provide a name for
-the column so that a different label appears in the output (this is called a
-column alias):
+The query works, but the result could be scanned more easily if the rows
+were presented in some order.  This can be done by adding an @code{ORDER
+BY name} clause to sort the output by name:
 
 @example
-mysql> SELECT name, (TO_DAYS(NOW())-TO_DAYS(birth))/365 AS age
+mysql> SELECT name, birth, CURRENT_DATE,
+    -> (YEAR(CURRENT_DATE)-YEAR(birth))
+    -> - (RIGHT(CURRENT_DATE,5)<RIGHT(birth,5))
+    -> AS age
     -> FROM pet ORDER BY name;
-+----------+------+
-| name     | age  |
-+----------+------+
-| Bowser   | 9.58 |
-| Buffy    | 9.88 |
-| Chirpy   | 0.55 |
-| Claws    | 5.04 |
-| Fang     | 8.59 |
-| Fluffy   | 6.15 |
-| Puffball | 0.00 |
-| Slim     | 2.92 |
-| Whistler | 1.30 |
-+----------+------+
++----------+------------+--------------+------+
+| name     | birth      | CURRENT_DATE | age  |
++----------+------------+--------------+------+
+| Bowser   | 1989-08-31 | 2001-08-29   |   11 |
+| Buffy    | 1989-05-13 | 2001-08-29   |   12 |
+| Chirpy   | 1998-09-11 | 2001-08-29   |    2 |
+| Claws    | 1994-03-17 | 2001-08-29   |    7 |
+| Fang     | 1990-08-27 | 2001-08-29   |   11 |
+| Fluffy   | 1993-02-04 | 2001-08-29   |    8 |
+| Puffball | 1999-03-30 | 2001-08-29   |    2 |
+| Slim     | 1996-04-29 | 2001-08-29   |    5 |
+| Whistler | 1997-12-09 | 2001-08-29   |    3 |
++----------+------------+--------------+------+
 @end example
 
 To sort the output by @code{age} rather than @code{name}, just use a
 different @code{ORDER BY} clause:
 
 @example
-mysql>  SELECT name, (TO_DAYS(NOW())-TO_DAYS(birth))/365 AS age
-    ->  FROM pet ORDER BY age;
-+----------+------+
-| name     | age  |
-+----------+------+
-| Puffball | 0.00 |
-| Chirpy   | 0.55 |
-| Whistler | 1.30 |
-| Slim     | 2.92 |
-| Claws    | 5.04 |
-| Fluffy   | 6.15 |
-| Fang     | 8.59 |
-| Bowser   | 9.58 |
-| Buffy    | 9.88 |
-+----------+------+
+mysql> SELECT name, birth, CURRENT_DATE,
+    -> (YEAR(CURRENT_DATE)-YEAR(birth))
+    -> - (RIGHT(CURRENT_DATE,5)<RIGHT(birth,5))
+    -> AS age
+    -> FROM pet ORDER BY age;
++----------+------------+--------------+------+
+| name     | birth      | CURRENT_DATE | age  |
++----------+------------+--------------+------+
+| Chirpy   | 1998-09-11 | 2001-08-29   |    2 |
+| Puffball | 1999-03-30 | 2001-08-29   |    2 |
+| Whistler | 1997-12-09 | 2001-08-29   |    3 |
+| Slim     | 1996-04-29 | 2001-08-29   |    5 |
+| Claws    | 1994-03-17 | 2001-08-29   |    7 |
+| Fluffy   | 1993-02-04 | 2001-08-29   |    8 |
+| Fang     | 1990-08-27 | 2001-08-29   |   11 |
+| Bowser   | 1989-08-31 | 2001-08-29   |   11 |
+| Buffy    | 1989-05-13 | 2001-08-29   |   12 |
++----------+------------+--------------+------+
 @end example
 
 A similar query can be used to determine age at death for animals that have
@@ -13248,12 +13262,14 @@ values, compute the difference between the @code{death} and @code{birth}
 values:
 
 @example
-mysql>  SELECT name, birth, death, (TO_DAYS(death)-TO_DAYS(birth))/365 AS age
-    ->  FROM pet WHERE death IS NOT NULL ORDER BY age;
+mysql> SELECT name, birth, death,
+    -> (YEAR(death)-YEAR(birth)) - (RIGHT(death,5)<RIGHT(birth,5))
+    -> AS age
+    -> FROM pet WHERE death IS NOT NULL ORDER BY age;
 +--------+------------+------------+------+
 | name   | birth      | death      | age  |
 +--------+------------+------------+------+
-| Bowser | 1989-08-31 | 1995-07-29 | 5.91 |
+| Bowser | 1989-08-31 | 1995-07-29 |    5 |
 +--------+------------+------------+------+
 @end example
 
@@ -13328,7 +13344,7 @@ mysql> SELECT name, birth FROM pet
 
 Note that @code{MONTH} returns a number between 1 and 12. And
 @code{MOD(something,12)} returns a number between 0 and 11. So the
-addition has to be after the @code{MOD()} otherwise we would go from
+addition has to be after the @code{MOD()}, otherwise we would go from
 November (11) to January (1).
 
 
@@ -46696,35 +46712,35 @@ not yet 100% confident in this code.
 @appendixsubsec Changes in release 3.23.42
 @itemize @bullet
 @item
-Enforce that all tables in a @code{MERGE} table comes from the same
+Enforce that all tables in a @code{MERGE} table come from the same
 database.
 @item
 Fixed bug with @code{LOAD DATA INFILE} and transactional tables.
 @item
 Fix bug when using @code{INSERT DELAYED} with wrong column definition.
 @item
-Fixed coredump during REPAIR of some particulary broken tables.
+Fixed coredump during @code{REPAIR} of some particularly broken tables.
 @item
 Fixed bug in @code{InnoDB} and @code{AUTO_INCREMENT} columns.
 @item
-Fixed critical bug in @code{InnoDB} and @code{BLOB}'s.  If one has used
-@code{BLOB}'s larger than 8K in an @code{InnoDB} table one must dump
-the table with @code{mysqldump}, drop it and restore it from the dump.
+Fixed critical bug in @code{InnoDB} and @code{BLOB} columns.  If one has
+used @code{BLOB} columns larger than 8K in an @code{InnoDB} table, one must
+dump the table with @code{mysqldump}, drop it and restore it from the dump.
 @item
 Applied large patch for OS/2 from Yuri Dario.
 @item
-Fixed problem with InnoDB when one could get the error @code{Can't
+Fixed problem with @code{InnoDB} when one could get the error @code{Can't
 execute the given command...} even when one didn't have an active
 transaction.
 @item
-Applied some minor fixes that concerns Gemini.
+Applied some minor fixes that concern Gemini.
 @item
 Use real arithmetic operations even in integer context if not
 all arguments are integers. (Fixes uncommon bug in some integer
-context).
+contexts).
 @item
-Don't force everything to lower cases on windows. (To fix problem
-with windows and @code{ALTER TABLE}).  Now @code{--lower_case_names}
+Don't force everything to lower cases on Windows. (To fix problem
+with Windows and @code{ALTER TABLE}).  Now @code{--lower_case_names}
 also works on Unix.
 @item
 Fixed that automatic rollback that is done when thread end doesn't lock
@@ -46740,7 +46756,7 @@ Added option @code{--sql-mode=option[,option[,option]]}.
 @xref{Command-line options}.
 @item
 Fixed possible problem with @code{shutdown} on Solaris where the
-@code{.pid} file wasn't deleted.
+@file{.pid} file wasn't deleted.
 @item
 InnoDB now supports < 4 GB rows. The former limit was 8000 bytes.
 @item