Joomla：使用PHP从页面访问级别获取用户组

Question

In Joomla 2.5.16:

1. Suppose user 100 belongs to user groups 14 and 16.
2. Suppose that the page he's currently viewing has an access level id of 6.
3. According to the table 'viewlevels' in the MySQL database, access level 6 is available for groups 8, 16 and 17

My goal is to find the "right" user group for this page. Since the user belongs to 2 user groups and one of them (16) is contained in the array of groups allowed to see this page, how can I query the database to find that group?

I tried:

$usr_id=100;
$access=6;

$query(SELECT rules from 'viewlevels' WHERE ???);

Table viewlevels has a structure like:

ID   | rules
6   |[8,16,17]

Table user_usergroup_map has a structure like:

User_id   |Group_id
100   |14
100   |16

Any help, please?

Answer 1

SELECT * FROM `#__viewlevels` AS `a` 
INNER JOIN `#__usergroups` AS `b` 
ON `a`.`rules` LIKE CONCAT('%',b.id,'%') 
INNER JOIN `#__user_usergroup_map` AS `m` 
ON m.group_id=b.id 
WHERE m.user_id = 100