......Certo che si, prova così:

SELECT tab_categorie.ID, tab_categorie.title, Query_info.info_name
FROM tab_categorie LEFT JOIN (
SELECT tab_infos.ID, tab_infos.info_name, categoria_id
FROM tab_infos INNER JOIN colleg_categorie_infos ON tab_infos.ID = colleg_categorie_infos.info_id
where tab_infos.ID=6
) as Query_info
ON tab_categorie.ID = Query_info.categoria_id;

Ciao
Mik