| From: | Tom Lane <tgl(at)sss(dot)pgh(dot)pa(dot)us> |
|---|---|
| To: | "Gan Uesli Starling" <alias(at)starling(dot)us> |
| Cc: | pgsql-novice(at)postgresql(dot)org |
| Subject: | Re: |
| Date: | 2006-01-31 15:48:10 |
| Message-ID: | 4307.1138722490@sss.pgh.pa.us |
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| Lists: | pgsql-novice |
"Gan Uesli Starling" <alias(at)starling(dot)us> writes:
> 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 think you can probably do this with SELECT DISTINCT ON (look at the
"weather reports" example in the SELECT reference page). DISTINCT ON
is nonstandard, but the bog-standard ways to do this involve messy,
inefficient sub-SELECT constructions.
regards, tom lane
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