Duplicating records to fill gap between dates

Question

I need to do something really weird, which is to create fake records in a view to fill the gap between posted dates of product prices.

Actually, my

Answer 1

I think I have a solution using an incremental approach toward the final result with CTE's:

with mindate as
(
  select min(price_date) as mindate from PRICES_TEST
)
,dates as
(
  select mindate.mindate + row_number() over (order by 1) - 1 as thedate from mindate,
    dual d connect by level <= floor(SYSDATE - mindate.mindate) + 1
)
,productdates as
(
  select p.product, d.thedate
  from (select distinct product from PRICES_TEST) p, dates d
)
,ranges as
(
  select
    pd.product,
    pd.thedate,
    (select max(PRICE_DATE) from PRICES_TEST p2
     where p2.product = pd.product and p2.PRICE_DATE <= pd.thedate) as mindate
    from productdates pd
)
select 
    r.thedate,
    r.product,
    p.price
from ranges r
inner join PRICES_TEST p on r.mindate = p.price_date and r.product = p.product
order by r.product, r.thedate

• mindate retrieves the earliest possible date in the data set
• dates generates a calendar of dates from earliest possible date to today.
• productdates cross joins all possible products with all possible dates
• ranges determines which price date applied at each date
• the final query links which price date applied to the actual price and filters out dates for which there are no relevant price dates via the inner join condition

Demo: http://www.sqlfiddle.com/#!4/e528f/126