Add missing data from previous month or year cumulatively

Question

Say I have the following data:

select 1 id, \'A\' name, \'2007\' year, \'04\' month,  5 sales  from dual union all
select 2 id, \'A\' name, \'2007\' year, \'         


        

Answer 1

A variation on @boneists approach, starting with your sample data in a CTE:

with t as (
  select 1 id, 'A' name, '2007' year, '04' month,  5 sales  from dual union all
  select 2 id, 'A' name, '2007' year, '05' month,  2 sales  from dual union all
  select 3 id, 'B' name, '2008' year, '12' month,  3 sales  from dual union all
  select 4 id, 'B' name, '2009' year, '12' month, 56 sales  from dual union all
  select 5 id, 'C' name, '2009' year, '08' month, 89 sales  from dual union all
  select 13 id,'B' name, '2016' year, '01' month, 10 sales  from dual union all
  select 14 id,'A' name, '2016' year, '02' month,  8 sales  from dual union all
  select 15 id,'D' name, '2016' year, '03' month, 12 sales  from dual union all
  select 16 id,'E' name, '2016' year, '04' month, 34 sales  from dual
),
y (year, rnk) as (
  select year, dense_rank() over (order by year)
  from (select distinct year from t)
),
r (name, year, month, sales, rnk) as (
  select t.name, t.year, t.month, t.sales, y.rnk
  from t
  join y on y.year = t.year
  union all
  select r.name, y.year, r.month, 0, y.rnk
  from y
  join r on r.rnk = y.rnk - 1
  where not exists (
    select 1 from t where t.year = y.year and t.month = r.month and t.name = r.name
  )
)
select name, year, month, sales,
  nvl(sum(sales) over (partition by name order by year, month
    rows between unbounded preceding and 1 preceding), 0) as opening_bal,
  nvl(sum(sales) over (partition by name order by year, month
    rows between unbounded preceding and current row), 0) as closing_bal
from r
order by year, month, name;

Which gets the same result too, though it also doesn't match the expected results in the question:

NAME YEAR MONTH      SALES OPENING_BAL CLOSING_BAL
---- ---- ----- ---------- ----------- -----------
A    2007 04             5           0           5
A    2007 05             2           5           7
A    2008 04             0           7           7
A    2008 05             0           7           7
B    2008 12             3           0           3
A    2009 04             0           7           7
A    2009 05             0           7           7
C    2009 08            89           0          89
B    2009 12            56           3          59
B    2016 01            10          59          69
A    2016 02             8           7          15
D    2016 03            12           0          12
A    2016 04             0          15          15
E    2016 04            34           0          34
A    2016 05             0          15          15
C    2016 08             0          89          89
B    2016 12             0          69          69

The y CTE (feel free to use more meaningful names!) generates all the distinct years from your original data, and also adds a ranking, so 2007 is 1, 2008 is 2, 2009 is 3, and 2016 is 4.

The r recursive CTE combines your actual data with dummy rows with zero sales, based on the name/month data from previous years.

From what that recursive CTE produces you can do your analytic cumulative sum to add the opening/closing balances. This is using windowing clauses to decide which sales values to include - essentially the opening and closing balances are the sum of all values up to this point, but opening doesn't include the current row.