ticket_id    topic_id
---------------------
0001      |   1
0002      |   3

topic_id   parent_id  sort   topic_name
---------------------------------------------
1        | 0         | 0    | request
2        | 1         | 1    | shipment
3        | 2         | 2    | problem

ticket_id  | category   | case_type   | sub_case_type
-----------------------------------------------------
0001       | request    |             |
0002       | request    | shipment    | problem

SELECT ticket.ticket_id, ticket.topic_id, help_topic.topic_name FROM ticket INNER JOIN help_topic ON ticket.topic_id = help_topic.topic_id