Expand table rows based on column value

Question

I have a table with two columns; EVENT_DATE date and RANG number the first column holds a date for an event while the second column is for the period of that event. here is a sample of data

| EVENT_DATE | RANG |
|------------|------|
| 03/01/2015 |    1 |
| 09/04/2015 |    3 |
| 15/10/2015 |    2 | 

is there any way to expand the EVENT_DATE by increment it based on the RANG value, so the output will be like,

| EVENT_DATE |
|------------|
| 03/01/2015 |
| 04/01/2015 |

| 09/04/2015 |
| 10/04/2015 |
| 11/04/2015 |
| 12/04/2015 |

| 15/10/2015 |
| 16/10/2015 |
| 17/10/2015 |

Answer 1

You could use a CTE to get a table with a sequence of numbers up to the highest rank in your table, and then join with that:

with nums as (
  select
    level-1 lvl
  from dual
  connect by
    level-1 < = (select max(rang) from foo)
)
select 
  foo.event_date + nums.lvl
, rang
from foo
join nums
  on nums.lvl <= foo.rang
order by
  foo.event_date + nums.lvl;