MySQL: trier les valeurs GROUP_CONCAT

En bref: existe-t-il un moyen de trier les valeurs dans une instruction GROUP_CONCAT?

Requete:

GROUP_CONCAT((SELECT GROUP_CONCAT(parent.name SEPARATOR " » ") 
FROM test_competence AS node, test_competence AS parent 
WHERE node.lft BETWEEN parent.lft AND parent.rgt 
  AND node.id = l.competence 
  AND parent.id != 1 
ORDER BY parent.lft) SEPARATOR "<br />\n") AS competences

J'obtiens cette ligne:

Artisanat »Menuiserie

Administration »Organisation

Je le veux comme ça:

Administration »Organisation

Artisanat »Menuiserie

Bien sûr, voir http://dev.mysql.com/doc/refman/...tions.html#function_group-concat :

SELECT student_name,
  GROUP_CONCAT(DISTINCT test_score ORDER BY test_score DESC SEPARATOR ' ')
  FROM student
  GROUP BY student_name;

Voulez-vous passer commande?

SELECT _key,            
COUNT(*) as cnt,            
GROUP_CONCAT(_value ORDER BY _value SEPARATOR ', ') as value_list      
FROM group_concat_test      
GROUP BY _key      
ORDER BY _key;