From: | James David Smith <james(dot)david(dot)smith(at)gmail(dot)com> |
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To: | pgsql-novice(at)postgresql(dot)org |
Subject: | Beginner Question... |
Date: | 2011-07-09 16:41:36 |
Message-ID: | CAMu32ABdWigZiqZv430BKDh0pye326Cert_yMv6K87x_hP4m2g@mail.gmail.com |
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Lists: | pgsql-novice |
Hi everyone,
Could someone help me with this question please? I have a table with
four columns:
- gps_id (primary key)
- date_time
- crimes_link (foreign key)
- osgb36_geom
The data in the table involves lots of gps tracks of different
journeys. They are grouped into journeys by the 'crimes_link' field.
So for example the first 50 rows have an identical 'crimes_link'
field, then the next 50 rows a different value in 'crimes_link', then
the next 50 rows a different one, etc. What I would like to do is to
select the beginning location of each journey. This query gives me the
date_time of the beginning of the journey:
SELECT crimes_link, MIN(date_time)
FROM camdengps3
GROUP BY crimes_link;
However I need to add the osgb36_geom column into the query and am unable too.
Any ideas how to do this please?
Thank you
James Smith
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