13.8.3 HELP Syntax

At the most general level, use contents to retrieve a list of the top-level help categories:

For a list of topics in a given help category, such as Data Types, use the category name:

For help on a specific help topic, such as the ASCII() function or the CREATE TABLE statement, use the associated keyword or keywords:

Empty result set

No match could be found for the search string.

Result set containing a single row with three columns

This means that the search string yielded a hit for the help topic. The result has three columns:

Example: HELP 'replace'

Yields:

name: REPLACE
description: Syntax:
REPLACE(str,from_str,to_str)

Returns the string str with all occurrences of the string from_str
replaced by the string to_str. REPLACE() performs a case-sensitive
match when searching for from_str.
example: mysql> SELECT REPLACE('www.mysql.com', 'w', 'Ww');
        -> 'WwWwWw.mysql.com'

Result set containing multiple rows with two columns

This means that the search string matched many help topics. The result set indicates the help topic names:

Example: HELP 'status'

Yields:

+-----------------------+----------------+
| name                  | is_it_category |
+-----------------------+----------------+
| SHOW                  | N              |
| SHOW ENGINE           | N              |
| SHOW MASTER STATUS    | N              |
| SHOW PROCEDURE STATUS | N              |
| SHOW SLAVE STATUS     | N              |
| SHOW STATUS           | N              |
| SHOW TABLE STATUS     | N              |
+-----------------------+----------------+

Result set containing multiple rows with three columns

This means the search string matches a category. The result set contains category entries:

Example: HELP 'functions'

Yields:

+----------------------+-------------------------+----------------+
| source_category_name | name                    | is_it_category |
+----------------------+-------------------------+----------------+
| Functions            | CREATE FUNCTION         | N              |
| Functions            | DROP FUNCTION           | N              |
| Functions            | Bit Functions           | Y              |
| Functions            | Comparison operators    | Y              |
| Functions            | Control flow functions  | Y              |
| Functions            | Date and Time Functions | Y              |
| Functions            | Encryption Functions    | Y              |
| Functions            | Information Functions   | Y              |
| Functions            | Logical operators       | Y              |
| Functions            | Miscellaneous Functions | Y              |
| Functions            | Numeric Functions       | Y              |
| Functions            | String Functions        | Y              |
+----------------------+-------------------------+----------------+