Bug #36879 mysql monitor "help max" and "help min" provider no help but "help min max" does
Submitted: 22 May 2008 8:32 Modified: 23 May 2008 12:37
Reporter: Janek Bogucki Email Updates:
Status: Closed Impact on me:
None 
Category:MySQL Server: Documentation Severity:S3 (Non-critical)
Version:5.0.51a-3ubuntu5.1-log OS:Linux (Kubuntu 8.04)
Assigned to: Paul DuBois CPU Architecture:Any

[22 May 2008 8:32] Janek Bogucki
Description:
To get online help for the MAX() function it is necessary to use "help min max" instead of "help max".

mysql> select version();
+------------------------+
| version()              |
+------------------------+
| 5.0.51a-3ubuntu5.1-log |
+------------------------+
1 row in set (0.00 sec)

mysql> help min;

Nothing found
Please try to run 'help contents' for a list of all accessible topics

mysql> help max;

Nothing found
Please try to run 'help contents' for a list of all accessible topics

mysql> help min max;
Name: 'MIN MAX'
Description:
Syntax:
MIN([DISTINCT] expr), MAX([DISTINCT] expr)

Returns the minimum or maximum value of expr. MIN() and MAX() may take
a string argument; in such cases they return the minimum or maximum
string value. See
http://dev.mysql.com/doc/refman/5.0/en/mysql-indexes.html. The DISTINCT
keyword can be used to find the minimum or maximum of the distinct
values of expr, however, this produces the same result as omitting
DISTINCT.

MIN() and MAX() return NULL if there were no matching rows.

URL: http://dev.mysql.com/doc/refman/5.0/en/group-by-functions.html

Examples:
mysql> SELECT student_name, MIN(test_score), MAX(test_score)
    ->        FROM student
    ->        GROUP BY student_name;

mysql>  

How to repeat:
Enter "help max" and see that help is reported as  unavailable.

Enter "help min max" and see that help is available

Suggested fix:
Make
[22 May 2008 13:45] MySQL Verification Team
Thank you for the bug report.
[22 May 2008 15:03] Paul DuBois
This is what I get:

mysql> help max
Name: 'MAX'
Description:
Syntax:
MAX([DISTINCT] expr)

Returns the maximum value of expr. MAX() may take a string argument; in
such cases, it returns the maximum string value. See
http://dev.mysql.com/doc/refman/5.0/en/mysql-indexes.html. The DISTINCT
keyword can be used to find the maximum of the distinct values of expr,
however, this produces the same result as omitting DISTINCT.

MAX() returns NULL if there were no matching rows.

URL: http://dev.mysql.com/doc/refman/5.0/en/group-by-functions.html

Examples:
mysql> SELECT student_name, MIN(test_score), MAX(test_score)
    ->        FROM student
    ->        GROUP BY student_name;

mysql> help min
Name: 'MIN'
Description:
Syntax:
MIN([DISTINCT] expr)

Returns the minimum value of expr. MIN() may take a string argument; in
such cases, it returns the minimum string value. See
http://dev.mysql.com/doc/refman/5.0/en/mysql-indexes.html. The DISTINCT
keyword can be used to find the minimum of the distinct values of expr,
however, this produces the same result as omitting DISTINCT.

MIN() returns NULL if there were no matching rows.

URL: http://dev.mysql.com/doc/refman/5.0/en/group-by-functions.html

Examples:
mysql> SELECT student_name, MIN(test_score), MAX(test_score)
    ->        FROM student
    ->        GROUP BY student_name;

mysql> help min max

Nothing found
Please try to run 'help contents' for a list of all accessible topics

It might be that you have an old version of the help information. Can you download a new version from here:

http://dev.mysql.com/doc/

(Scroll down to "MySQL Help Tables")

Do you get the same result with updated help information?
[23 May 2008 9:40] Janek Bogucki
This bug goes away with the updated help data from http://downloads.mysql.com/docs/fill_help_tables-5.0.sql.zip

This bug has been reported on https://bugs.launchpad.net. Link to follow.
[23 May 2008 9:42] Janek Bogucki
https://bugs.launchpad.net/ubuntu/+source/mysql-dfsg-5.0/+bug/234268
[23 May 2008 12:37] Paul DuBois
Thank you for your bug report. This issue has been addressed in the documentation. The updated documentation will appear on our website shortly, and will be included in the next release of the relevant products.

The current help files have already fixed the problem. These will be included in future MySQL releases.