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 made a few changes to Wolf's excellent answer.

I replaced the subquery factoring (WITH) with a regular subquery in the connect by. This makes the code a little simpler. (Although this type of code looks weird at first either way, so there may not be a huge gain here.)

Most significantly, I used a partition outer join instead of a cross join and outer join. Partition outer joins are also kind of strange, but they are meant for exactly this type of situation. This makes the code simpler, and should improve performance.

select
    price_dates.price_date
    ,product
    ,last_value(price ignore nulls) over (order by product, price_dates.price_date) price
from
(
    select trunc(sysdate) - level + 1 price_date
    from dual
    connect by level <= trunc(sysdate) -
        (select min(trunc(price_date)) from prices_test) + 1
) price_dates
left outer join prices_test
    partition by (prices_test.product)
    on price_dates.price_date = prices_test.price_date;