mysql.help_topic is one of the four tables used by the HELP command. It is populated when the server is installed by the fill_help_table.sql script. The other help tables are help_relation, help_category and help_keyword.
In MariaDB 10.4 and later, this table uses the Aria storage engine.
In MariaDB 10.3 and before, this table uses the MyISAM storage engine.
The mysql.help_topic table contains the following fields:
| Field | Type | Null | Key | Default | Description |
|---|---|---|---|---|---|
help_topic_id |
int(10) unsigned |
NO | PRI | NULL |
|
name |
char(64) |
NO | UNI | NULL |
|
help_category_id |
smallint(5) unsigned |
NO | NULL |
||
description |
text |
NO | NULL |
||
example |
text |
NO | NULL |
||
url |
char(128) |
NO | NULL |
SELECT * FROM help_topic\G;
...
*************************** 508. row ***************************
help_topic_id: 507
name: FIND_IN_SET
help_category_id: 37
description: Syntax:
FIND_IN_SET(str,strlist)
Returns a value in the range of 1 to N if the string str is in the
string list strlist consisting of N substrings. A string list is a
string composed of substrings separated by "," characters. If the first
argument is a constant string and the second is a column of type SET,
the FIND_IN_SET() function is optimized to use bit arithmetic. Returns
0 if str is not in strlist or if strlist is the empty string. Returns
NULL if either argument is NULL. This function does not work properly
if the first argument contains a comma (",") character.
URL: http://dev.mysql.com/doc/refman/5.5/en/string-functions.html
example: mysql> SELECT FIND_IN_SET('b','a,b,c,d');
-> 2
url: http://dev.mysql.com/doc/refman/5.5/en/string-functions.html
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https://mariadb.com/kb/en/mysqlhelp_topic-table/