Select: add a column based on sub select - sql

Question

I have the following scenario:
Using SQLDbx - database: DB2
The following SQL
WITH priceanddates AS
(
SELECT a.*
FROM FPRICE a
INNER JOIN
(
SELECT edate, MAX(idx) maxIdx
FROM FPRICE
WHERE price>0
GROUP BY edate
) b ON a.edate = b.edate AND a.idx = b.maxIdx
)
SELECT *
FROM priceanddates
WHERE fcode='XYZ'
ORDER BY edate
yields:
fcode edate idx price
XYZ 2010-09-17 2 34,3
XYZ 2010-09-20 2 34,3
XYZ 2010-09-21 2 34,3
XYZ 2010-09-22 2 34,3
XYZ 2010-09-23 2 35,7
XYZ 2010-09-24 2 34,5
XYZ 2010-09-27 2 35,5
BUT - I need something more...I would like to add a column in the final select which says something about the date's validity, like this:
fcode edate_from edate_to idx price
XYZ 2010-09-17 2010-09-20 2 34,3
XYZ 2010-09-20 2010-09-21 2 34,3
XYZ 2010-09-21 2010-09-22 2 34,3
XYZ 2010-09-22 2010-09-23 2 34,3
XYZ 2010-09-23 2010-09-24 2 35,7
XYZ 2010-09-24 2010-09-27 2 34,5
XYZ 2010-09-27 2010-09-30 2 35,5
So, edate_to is based on the "next" edate_from (as the view is currently ordered by date), or (as I hopefully deduced correctly) edate_to is simply the MIN(edate larger than "current" edate)
The final cutoff date for all dates in the DB is 2010-09-30, alas the last edate_to must always be 2010-09-30.
Obviously, I am not very skilled when it comes to writing SQL, hopefully someone can point me in the right direction - or even better - provide a solution :)
I did search around SO for a while, but I couldn't really find what I was looking for...
Cheers, Dritt.

Answer 1

Maybe:
WITH priceanddates AS
(
SELECT a.*,
(SELECT COALESCE(MIN(aa.edate), '2010-09-30')
FROM FPRICE aa
WHERE aa.edate > a.edate) AS edate_to
FROM FPRICE a
INNER JOIN
(
SELECT edate, MAX(idx) maxIdx
FROM FPRICE
WHERE price>0
GROUP BY edate
) b ON a.edate = b.edate AND a.idx = b.maxIdx
)
SELECT *
FROM priceanddates
WHERE fcode='XYZ'
ORDER BY edate

Answer 2

Use the new LEAD function.
More on it here.
WITH priceanddates AS
(
SELECT a.*
FROM FPRICE a
INNER JOIN
(
SELECT edate, MAX(idx) maxIdx
FROM FPRICE
WHERE price>0
GROUP BY edate
) b ON a.edate = b.edate AND a.idx = b.maxIdx
)
SELECT fcode
, edate AS edate_from
, LEAD (edate) OVER (ORDER BY edate) AS edate_to
, idx
, price
FROM priceanddates
WHERE fcode='XYZ'
ORDER BY edate