RE: To function or not to function, that is the question at hand

Why not just create the function to convert a date and then use that function in your where clause?

CREATE FUNCTION MYLIB.DATEFMT (
YY DEC (2, 0)
MM DEC (2, 0)
DD DEC (2, 0))
RETURNS DATE
LANGUAGE SQL
BEGIN
RETURN (
DATE (
'20' CONCAT YY CONCAT MM CONCAT DD CONCAT '000000'
)
) ;
END ;

Select * from mylib.myfile where date >= mylib.datefmt(YY,MM,DD)

I'm not sure how this would work performance wise, but it should work.

-Tom

-----Original Message-----
From: midrange-l-bounces@xxxxxxxxxxxx [mailto:midrange-l-bounces@xxxxxxxxxxxx] On Behalf Of Mike Wills
Sent: Wednesday, February 09, 2011 2:24 PM
To: midrange-l@xxxxxxxxxxxx
Subject: Re: To function or not to function, that is the question at hand

I might be able to work with this. But not quite where I was going with this either. What I wrote before was the old query I had. Now I need it to look more like

where date >= (SELECT DATE(CONCAT('20', CONCAT(YY, CONCAT('-', CONCAT( MM, (CONCAT('-', DD))))))) FROM LIB/FILE') and date <= (SELECT DATE(CONCAT('20', CONCAT(EYY, CONCAT('-', CONCAT(EMM, (CONCAT('-',
EDD))))))) FROM LIB/FILE')

I was hoping to return a single value so I don't clutter my statements with all of that junk.

--
Mike Wills
http://mikewills.me


On Wed, Feb 9, 2011 at 4:06 PM, Christen, Duane
<Duane.Christen@xxxxxxxxxx>wrote:

Mike;

If the table where your YY MM DD date is stored contains a single
record, as your sql implies, then I would create a view:

Create View PeriodOpenDate
SELECT DATE(CONCAT('20', CONCAT(YY, CONCAT('-', CONCAT( MM,
(CONCAT('-', DD))))))) as openDate FROM LIB/FILE;


Duane Christen


-----Original Message-----
From: midrange-l-bounces@xxxxxxxxxxxx [mailto:
midrange-l-bounces@xxxxxxxxxxxx] On Behalf Of Mike Wills
Sent: Wednesday, February 09, 2011 3:39 PM
To: midrange-l@xxxxxxxxxxxx
Subject: To function or not to function, that is the question at hand

I am working on some SQL statements for an ASP.NET application. One of
the things that is required is to only display information in an open period.
The period is updated automatically by the vendor software as the
previous period is closed. So I finding myself doing a bunch of sub selects like:

where date >= (SELECT DATE(CONCAT('20', CONCAT(YY, CONCAT('-',
CONCAT( MM, (CONCAT('-', DD))))))) FROM LIB/FILE')

Yes, each portion of the date is in separate fields.

Would making this query a function make the query more efficient? I
have never created a function before how would I do that? My thought
is having something like:

IsInRange(date)

So I can do "WHERE IsInRange(date)".

Or is there a better way?

--
Mike Wills
http://mikewills.me
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