Re: Please help me write a query
От | Justin Graf |
---|---|
Тема | Re: Please help me write a query |
Дата | |
Msg-id | 4BFE9AF8.7000206@magwerks.com обсуждение исходный текст |
Ответ на | Please help me write a query (Nikolas Everett <nik9000@gmail.com>) |
Список | pgsql-general |
On 5/27/2010 9:04 AM, Nikolas Everett wrote: > Say I have a table that stores state transitions over time like so: > id, transitionable_id, state1, state2, timestamp > > I'm trying to write a query that coalesces changes in state2 away to > produce just a list of transitions of state1. I guess it would look > something like > > SELECT state1, FIRST(timestamp) > FROM table > > but I have no idea how to aggregate just the repeated state1 rows. if i understand what your after Select distinct transitinable_id, state1, min(timestamp) from table group by transitinable_id, state1 All legitimate Magwerks Corporation quotations are sent in a .PDF file attachment with a unique ID number generated by ourproprietary quotation system. Quotations received via any other form of communication will not be honored. CONFIDENTIALITY NOTICE: This e-mail, including attachments, may contain legally privileged, confidential or other informationproprietary to Magwerks Corporation and is intended solely for the use of the individual to whom it addresses.If the reader of this e-mail is not the intended recipient or authorized agent, the reader is hereby notified thatany unauthorized viewing, dissemination, distribution or copying of this e-mail is strictly prohibited. If you have receivedthis e-mail in error, please notify the sender by replying to this message and destroy all occurrences of this e-mailimmediately. Thank you.
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