gianlucas Consegui o que queria usando o SUBSTRING_INDEX e SUBSTRING. Vai servir para o meu uso, porque os campos serão sempre com 5 caracteres. Ex: 01:30.
SELECT T0.number AS 'Ticket',
T1.username AS 'Agente',
(SELECT priority_desc FROM ost_ticket_priority WHERE T7.priority = priority_id) AS 'Prioridade',
(SELECT topic FROM ost_help_topic WHERE topic_id = T0.topic_id) AS 'Tópico de Ajuda',
A1.timestamp AS 'Data do Registro',
(SELECT Label FROM ost_form_field WHERE id = SUBSTRING(SUBSTRING_INDEX(A1.data, 'fields', -1),5,2)) AS 'Campo',
SUBSTRING(A1.data,-9,5) AS 'Horas',
REPLACE(REPLACE(A2.body, "<p>", ""),"</p>","") AS 'Observação'
FROM ost_ticket T0
JOIN ost_staff T1 ON T1.staff_id = T0.staff_id
INNER JOIN ost_ticket__cdata T7 ON T0.ticket_id = T7.ticket_id
inner join ost_thread A0 ON A0.id = T0.ticket_id
INNER join ost_thread_event A1 ON A1.thread_id = A0.id
left JOIN ost_thread_entry A2 ON A2.thread_id = A1.thread_id AND A2.created = A1.timestamp AND A2.type='N'
