Assist in Cleaning a MySQL Join Query to Find Changes Between Rows -


table size ~500,000 rows, 137mb, query time 1.591 sec

i junior programmer testing mettle on our mysql based otrs ticket database. i'm looking instances in ticket moves between queues. indicator move exists on same row new queue, , have setup query attempts return previous value of same column in same ticket id.

example of ticket in table:

id    history_type_id    ticket_id    queue_id            create_time 377                 1           30           2    2012-09-14 11:06:02 378                21           30           2    2012-09-14 11:06:02 379                12           30           2    2012-09-14 11:06:02 380                 4           30           2    2012-09-14 11:06:02 381                16           30           8    2012-09-14 11:08:29 383                16           30           2    2012-09-14 11:09:54 384                17           30           2    2012-09-14 11:11:28                           ***  stuff happens  *** 396                27           30           2    2012-09-14 11:22:06 397                18           30           2    2012-09-14 11:22:06

the rows in question 380, 381, , 383. history_type_id value move 16, , row above 381 has previous queue_id of ticket. able build query checks previous id value before id value history_type_id of 16 , shares same ticket_id , return queue_id of row (or assume. 100% self taught point). can assume, id , create_time not limited per ticket, , cannot used reliably sort.

here query:

select oldq.id,        oldq.queue_id oldone,        oldq.create_time firstq,        newq.id,        newq.queue_id newone,        newq.create_time lastq,        oldq.ticket_id  ticket_history oldq     join ticket_history newq         on oldq.id < newq.id          , oldq.ticket_id = newq.ticket_id newq.history_type_id = '16' order newq.ticket_id,          newq.id,          oldq.id

this "works" in ugly , unacceptable way, looks every value of oldq.id per ticket_id rather 1 before newq.id, , hit roadblock. have usable data, far more need. example, here output above ticket:

 id  oldone               firstq   id  newone                 lastq   ticket_id 377       2  2012-09-14 11:06:02  381       8   2012-09-14 11:08:29          30 378       2  2012-09-14 11:06:02  381       8   2012-09-14 11:08:29          30 379       2  2012-09-14 11:06:02  381       8   2012-09-14 11:08:29          30 380       2  2012-09-14 11:06:02  381       8   2012-09-14 11:08:29          30 377       2  2012-09-14 11:06:02  383       2   2012-09-14 11:09:54          30 378       2  2012-09-14 11:06:02  383       2   2012-09-14 11:09:54          30 379       2  2012-09-14 11:06:02  383       2   2012-09-14 11:09:54          30 380       2  2012-09-14 11:06:02  383       2   2012-09-14 11:09:54          30 381       8  2012-09-14 11:08:29  383       2   2012-09-14 11:09:54          30

where i'm attempting drive return such this:

 id  oldone               firstq   id  newone                 lastq   ticket_id 380       2  2012-09-14 11:06:02  381       8   2012-09-14 11:08:29          30 381       8  2012-09-14 11:08:29  383       2   2012-09-14 11:09:54          30

been puzzling 1 hours today, pleased when query ran, if these numbers can come alive, ecstatic

sytharin, haven't been able test yet, solution believe work follows:

select      oldq.id,     oldq.queue_id oldone,     oldq.create_time firstq,     newq.id,     newq.queue_id newone,     newq.create_time lastq,     oldq.ticket_id  ticket_history oldq join ticket_history newq     on newq.id - 1 = oldq.id     , oldq.ticket_id = newq.ticket_id      newq.history_type_id = '16' order      newq.ticket_id,     newq.id,     oldq.id

upon modifying join statement @ oldq.id directly behind newq.id, should limit results single row directly preceding newq.id. again, untested, small change in query see if works.


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