Conditional Concatenation of SQL Query results

I'd like to show the results of a query concatenated with their self based on a value.

I have this query

        SELECT CONCAT(cl.`name`,\',\') as name
        FROM `'._DB_PREFIX_.'category_lang` AS cl
        INNER JOIN `'._DB_PREFIX_.'category` AS c ON (cl.`id_category` = c.`id_category`)
        WHERE cl.`name` LIKE \'%'.pSQL($searchData).'%\'
        AND c.`level_depth` NOT IN (0, 1, 4, 5) and cl.`id_lang`='.(int)$context->language->id.'

which shows the list of available location for a booking platform, based on what the user is typing.

This is the results list:

Lisbon
Ortisei
Palermo
Polignano a Mare
Portugal

The inner join table results is the following

as you can see there are different level_depth for each entry of the table.

I would like to CONCAT all the entries with level_depth=3 with the name of their id_parent and showing all the entries with level_depth=2 without any concatenation.

The above results should become:

Lisbon, Portugal
Ortisei, Italy
Palermo, Italy
Polignano a Mare, Italy
Portugal