Oracle-L: SQL Join or Subquery

From: Gary Chambers <gc22_at_lucent.com>
Date: Wed, 17 Jul 2002 13:54:14 -0800
Message-ID: <F001.0049AC98.20020717135414@fatcity.com>

All...

I have a question about a query over which I've been racking my brain for weeks, and I can't find a reference to adequately assist me.

Given a table of temperature sensors, and a table of readings from those sensors, how might I grab the max (hence latest or current) temperature reading for each sensor? The relevant fields in the tables are timestamp and temp_c (temperature table), and sensorid (both temperature and sensor tables).

I'm fairly certain that I'm overlooking something very elementary, and I feel it should be simple and straightforward, but I think I'm being stymied by the use of aggregate functions in my query. I can provide examples of my failed attempts, if you'd like. Thanks in advance for any assistance you can provide.

Gary Chambers

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Author: Gary Chambers
  INET: gc22_at_lucent.com

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Received on Wed Jul 17 2002 - 16:54:14 CDT