[postgis-users] Help with query

Obe, Regina robe.dnd at cityofboston.gov
Fri Nov 3 13:04:14 PST 2006

I'm going to assume your table has 2 fields
ignition_on which is a boolean
actiontime which is a timestamp
and your table is called ignition_log
I would try the following - haven't tested it so don't know if it will
SELECT igoff.actiontime as ignition_off_time, MIN(igon.actiontime) as
ignition_on_time,  MIN(igon.actiontime) - igoff.actiontime as
FROM ignition_log igoff INNER JOIN ignition_log igon 
        ON igoff.actiontime < igon.actiontime AND igoff.ignition_on =
false AND igon.ignition_on = true
GROUP BY igoff.actiontime


From: postgis-users-bounces at postgis.refractions.net
[mailto:postgis-users-bounces at postgis.refractions.net] On Behalf Of
Pedro Doria Meunier
Sent: Friday, November 03, 2006 2:31 PM
To: 'PostGIS Users Discussion'
Subject: [postgis-users] Help with query

This is probably not the best place to be asking such a (lame) question
but perhaps someone is gracious enough to lend me a hand... ;-)


I have the following setup in a table:


The first record which is to be found (ok easy enough :D) with a
timestamp meets a certain condition (ignition off)

The following record is for the event of ignition on again with a


So the question here is: how can I compute the time difference between
these two records in a single query?

Better yet: finding all the records that meet the first condition
(ignition off) and the immediately following records as to compute the
time difference. ;-)


Thanks in advance!


Pedro Doria Meunier

(351) 91 302 49 72 - (351) 96 247 99 12

MSN - pdoriam at hotmail.com

ICQ - 308-182-126

Skype: pdoriam


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