query problem - Mailing list pgsql-sql

From Marco Muratori
Subject query problem
Date
Msg-id Pine.LNX.4.30.0208301824330.25859-100000@marco.intranet
Whole thread Raw
Responses Re: query problem  (Josh Berkus <josh@agliodbs.com>)
List pgsql-sql
Hi
suppose I have the following situation:
 city            date
---------+-----------------------
London   | 2002-08-08 07:05:16+00
London   | 2002-07-30 13:08:22+00
London   | 2002-07-30 07:39:15+00
London   | 2002-07-29 17:51:47+00
London   | 2002-07-29 17:45:49+00
London   | 2002-07-29 17:45:47+00
Paris    | 2002-04-08 15:04:28+00
Paris    | 2002-03-29 17:22:18+00
Paris    | 2002-02-15 12:50:32+00
Paris    | 2002-01-22 11:40:22+00
Paris    | 2002-01-07 17:41:23+00
Paris    | 2001-11-12 16:37:37+00
Paris    | 2001-11-05 15:28:23+00
Paris    | 2001-11-05 08:21:19+00
Oslo     | 2002-07-19 15:42:20+00
Oslo     | 2002-07-19 15:42:18+00
Oslo     | 2002-07-18 10:03:58+00
Oslo     | 2002-07-18 08:56:30+00
Oslo     | 2002-07-17 17:17:27+00
Oslo     | 2002-07-17 16:11:38+00

For each city I have a couple of dates in DESC order.
For each city i need to get the first record which date
comes after a given date. If the given date was for example
"2002-07-19 15:39:15+00", I would get the following
records:

London   | 2002-07-29 17:45:47+00
Oslo     | 2002-07-19 15:42:18+00

Is there a way to obtain this records by performing one
single query and not by making for each city something like
"SELECT city,date FROM table WHERE city='London' AND date>'2002-07-19
15:39:15+00' ORDER BY date ASC LIMIT 1;"?
Thanks.



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