SQL-Befehl: Dokumentation

SELECT unit. * , type.typename, unit.user_ID, equipment.description, equipment.id, sum( unit.distance ) AS myd
FROM TYPE , equipment
LEFT JOIN unit ON unit.equipment_id = equipment.id
WHERE type.id = equipment.type_id
AND equipment.user_id =3
GROUP BY myd
LIMIT 0 , 30

MySQL meldet: Dokumentation
#1056 - Can't group on 'myd'