Re: using a generated series in function

From: Misa Simic <misa(dot)simic(at)gmail(dot)com>
To: John Fabiani <johnf(at)jfcomputer(dot)com>
Cc: pgsql-sql(at)postgresql(dot)org
Subject: Re: using a generated series in function
Date: 2011-12-16 12:08:20
Message-ID: CAH3i69kNEYm0DPhe-rCHVq62ejzA6_xizdxFV4oT-fyj8vRw4w@mail.gmail.com
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That is good - that you solved it...

Well - in from it does not need to be just from table...

it needs to be some set of rows... is it Table or function (SELECT i FROM
generate_series(0, 84, 7) i - is actually from function...) or from View...

SELECT * FROM (SELECT * FROM Table1) as InlineView

Also works becouse of subquery also returns some set of rows...

Kind Regrads,

Misa

2011/12/16 John Fabiani <johnf(at)jfcomputer(dot)com>

> I have solved my problem. But this still does not explain the idea of
> "from"????
>
> select foo.week_date, xchromasun._chromasun_getqtyordered(303,
> foo.week_date)
> as week_qty from
> (select ((date_trunc('week', '2011-11-20'::date )::date) + (i+6)) as
> week_date from generate_series(0,84,7)
> i ) as foo
>
> The above works!
>
> Johnf
> On Friday, December 16, 2011 02:46:18 AM John Fabiani wrote:
> > Actually what would the "from" be - this could be a newbie issue here?
> > Neither statement requires a "from" because neither of the statements
> uses a
> > table - I think! I'll try to add one but the first part is a function
> like
> > a any other function. What is the "from" when you do:
> > "select now()" - really I don't know!
> >
> > The second part is tricky because I don't really understand it.
> Howerver, I
> > have used it several times (got it off the web somewhere) but only in a
> > "for loop". If I just run it by it's self it generates a table of dates.
> > Therefore, I have always thought of it as a function. Again, like
> "select
> > now()"
> >
> > So I know this must sound like I'm sort of idiot - just never considered
> the
> > second half (the part that provides the dates) anything other than a
> > postgres function.
> >
> > Johnf
> >
> > On Friday, December 16, 2011 01:30:53 AM Misa Simic wrote:
> > > It is not totally clear to me what are u trying to do... But in second
> > > query it seems there is missing "from"
> > >
> > > It is as
> > >
> > > SELECT week-date::date AS week-date WHERE week-date in (subquery which
> > > have from)
> > >
> > > So week-date column in main query does not exist..
> > >
> > > Sent from my Windows Phone From: John Fabiani
> > > Sent: 16 December 2011 05:16
> > > To: pgsql-sql(at)postgresql(dot)org
> > > Subject: [SQL] using a generated series in function
> > > Hi,
> > >
> > > I am attempting (without success) use the generated series of dates
> that
> > > come from:
> > > select (cast(date_trunc('week', '2011-11-20'::date ) as date) + (i+6))
> > > as
> > > week_date from generate_series(0,84,7) i
> > >
> > > in a function.
> > > select function_name(integer, date); -- function returns a numeric
> > >
> > > This does NOT work:
> > > select (function_name(303, week_date::date)) as week_date where
> > > week_date in (select (cast(date_trunc('week', '2011-11-20'::date ) as
> > > date) + (i+6)) as week_date from generate_series(0,84,7) i )
> > >
> > > The error is:
> > > ERROR: column "week_date" does not exist
> > > LINE 1: select (xchromasun._chromasun_getqtyordered(303, week_date::...
> > >
> > > I hope I can do this? What am I doing wrong?
> > > Johnf
>
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