Re: Extract from date field

On 17 June 2011 20:12, James David Smith <james(dot)david(dot)smith(at)gmail(dot)com> wrote:
> Hey,
>
> I realise it's probably poor form to reply to your own question, but I
> thought I'd just say I've managed to do this! Well, question 2 anyway.
> To extract a DAY from a date field, and keep a leading zero, I have
> used the 'lpad' function like so:
>
> SELECT lpad (cast((EXTRACT(DAY from timestamp '2010-01-01')) as
> varchar), 2, '0')
>
> Except that in my query it looks like this:
>
> (SELECT lpad (cast((EXTRACT(DAY from date_of_incident)) as varchar), 2, '0'))
>
> I thought I'd post this incase it's off use to anyone else.
>
> Just need to figure out how to convert it all to a integer now...

Ah, I believe I've replied to this on Twitter, but I'll post here too.
You can use the very handy to_char function to convert your date into
a formatted string. (see
http://www.postgresql.org/docs/9.0/static/functions-formatting.html )
So you'd end up with:

ALTER TABLE camdengps2
ADD COLUMN camdencrimes_link varchar;
UPDATE camdengps2
SET camdencrimes_link=(to_char(date_time, 'DDMMYYYY') || incident)::int

Hope that solves it for you.

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Thom Brown
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