From: | "Gan Uesli Starling" <alias(at)starling(dot)us> |
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To: | pgsql-novice(at)postgresql(dot)org |
Subject: | |
Date: | 2006-01-31 15:10:28 |
Message-ID: | 20060131151028.17040.qmail@mail_102.selectedhosting.com |
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Thread: | |
Lists: | pgsql-novice |
My problem is this:
I have a table 'history' with columns for ''date_time', 'event', 'sensor'.
The 'event' column may contain 'Calibrated', 'Damaged', 'Repaired'.
Since it is a history, the same sensor may be listed multiple times with a
date for each event.
I want only the most recent calibration event for undamaged sensors.
I am trying to figure out how to winnow out in a single query (no
intermediate
tables) the most recent event for each sensor which has been 'Calibrated' or
'Repaired' not 'Damaged' afterwards.
I had thought it would be so simple. But after much wrangling I seem to be
stumped.
--
Mistera Sturno - Rarest Extinct Bird
<(+)__ Gan Uesli Starling
((__/)=- Kalamazoo, MI, USA
`||`
++ http://starling.us
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