Re: Select only active entries

From: "Rob Richardson" <Rob(dot)Richardson(at)rad-con(dot)com>
To: <pgsql-novice(at)postgresql(dot)org>
Subject: Re: Select only active entries
Date: 2010-07-26 15:03:42
Message-ID: 04A6DB42D2BA534FAC77B90562A6A03D01466958@server.rad-con.local
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Carel,

It is very poor design to assume that records in a database have any
order whatsoever. You are setting yourself up for some very
hard-to-find bugs that way. If you merely add a column named
"insert_time" of type timestamp and set its default value to "now()",
you will have a guaranteed way to know the order in which records were
inserted, and you don't have to change any query that references your
table. Or, you can recreate the table with a column of type
"bigserial". That will automatically set up a sequence that will number
the records in the order in which they were inserted.

HTH,

RobR



They are not time stamped but in sequence. The latest active one
is basically if you look at number 5. It goes from active to inactive
to active again at time of the query. I want to know if the last entry
of ID 5 was active or inactive. And so-forth for all the rest of the
ID's. So only select the IDs that were active on their last entry into
the database.

Is there a way of querying the data to obtain only the last
entry in the table for a given ID?


--

Carel Combrink

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