Oracle SQL: Get the previous values

I have two columns table: Id, and value.

ID	Value
1
2	AA
3
4	BB
5
6
7
8	CC
9

I need a query in Oracle to return the result as

ID	Value
1
2	AA
3	AA
4	BB
5	BB
6	BB
7	BB
8	CC
9	CC

Is there anyway to do this? Thanks in advance.

Answer

select id, last_value(value IGNORE NULLS) over (order by id) as modified_value
from   your_table
;