Inverse of count

Question

I have the below data set -
Order_id Item Qty
1 A1 3
2 A2 2
3 A3 3
My desired output (With only one SQL query) is mentioned below-
Order_id Item Qty
1 A1 1
1 A1 1
1 A1 1
2 A2 1
2 A2 1
3 A3 1
3 A3 1
3 A3 1
How do I do this?

Answer 1

Another way would be :
SQL> with sample_data as (
  2   select 1 order_id, 'A1' item, 3 qty from dual union all
  3   select 2, 'A2', 2 from dual union all
  4   select 3, 'A3', 3 from dual
  5  )
  6  select t1.order_id
  7       , t1.item
  8       , t2.column_value as qty
  9  from sample_data t1
10     , table(
11         cast(
12           multiset(
13             select 1 from dual connect by level <= t1.qty
14           ) as sys.odcinumberlist
15         )
16       ) t2
17  ;
  ORDER_ID ITEM        QTY
         1 A1            1
         1 A1            1
         1 A1            1
         2 A2            1
         2 A2            1
         3 A3            1
         3 A3            1
         3 A3            1
8 rows selected
or, using recursive subquery factoring (11.2) :
SQL> with sample_data as (
  2   select 1 order_id, 'A1' item, 3 qty from dual union all
  3   select 2, 'A2', 2 from dual union all
  4   select 3, 'A3', 3 from dual
  5  ),
  6  dataset (order_id, item, qty, sofar) as
  7  (
  8    select order_id
  9         , item
10         , qty
11         , 1
12    from sample_data
13    union all
14    select order_id, item, qty, sofar+1
15    from dataset
16    where sofar < qty
17  )
18  search depth first by order_id set seq
19  select order_id, item, 1 as qty
20  from dataset
21  ;
  ORDER_ID ITEM        QTY
         1 A1            1
         1 A1            1
         1 A1            1
         2 A2            1
         2 A2            1
         3 A3            1
         3 A3            1
         3 A3            1
8 rows selected