Oracle 21c

By using db<>fiddle, you agree to license everything you submit by Creative Commons CC0.
create table Stock(Item	varchar(50), Current_Stock	int, Value int);
insert into Stock values('Blade'	,8	,40);
1 rows affected

insert into Stock values('Table'	,15	,100);
1 rows affected

insert into Stock values('Screen'	,3	,30);
1 rows affected

create table Receipts(Item varchar(50), Receipt_Date date, Quantity int);
insert into Receipts values('Blade','3 Jan 2020',	20);
1 rows affected

insert into Receipts values('Blade','10 Dec 2021',	10);
1 rows affected

insert into Receipts values('Blade','5 Jan 2022',	5);
1 rows affected

insert into Receipts values('Table','4 Mar 2020',	10);
1 rows affected

insert into Receipts values('Table','1 May 2021',	7);
1 rows affected

insert into Receipts values('Table','10 Jul 2021',	5);
1 rows affected

insert into Receipts values('Table','1 Aug 2021',	5);
1 rows affected

with Recepts_with_runningtotal_qty as
(
   select Item , Receipt_Date, Quantity, sum(Quantity)over(partition by Item order by Receipt_Date desc) running_total_qty from Receipts
),
current_stock as
(
   select Item , Current_Stock, Value, (select max(Receipt_Date) from Recepts_with_runningtotal_qty r where r.running_total_qty>s.current_stock and s.Item=r.Item)Receipt_Date
   from Stock s
)
select Item, Current_Stock, Value, Receipt_Date,(to_date('1 Feb 2022','DD MM YY')-Receipt_Date)Age_in_Days from current_stock


ITEM
CURRENT_STOCK
VALUE
RECEIPT_DATE
AGE_IN_DAYS


Blade
8
40
10-DEC-21
53

Table
15
100
01-MAY-21
276

Screen
3
30
null
null


select Item, Current_Stock, Value, Receipt_Date,(to_date('1 Feb 2022','DD MM YY')-Receipt_Date)Age_in_Days
from
(
  select Item, Current_Stock, Value, Receipt_Date,Quantity, Running_Total_Qty,
  row_number()over(partition by Item order by Receipt_Date desc)rn
  from
  (
    Select S.Item, S.Current_Stock, S.Value, R.Receipt_date, R.Quantity,
    sum(Quantity)over(partition by R.Item order by Receipt_Date desc) running_total_qty
    From Stock S 
    Left outer join Receipts R On (S.Item = R.Item)
  )
  where Running_Total_Qty>= Current_Stock or Running_Total_Qty is null
)
where rn=1


ITEM
CURRENT_STOCK
VALUE
RECEIPT_DATE
AGE_IN_DAYS


Blade
8
40
10-DEC-21
53

Screen
3
30
null
null

Table
15
100
01-MAY-21
276
ITEM	CURRENT_STOCK	VALUE	RECEIPT_DATE	AGE_IN_DAYS
Blade	8	40	10-DEC-21	53
Table	15	100	01-MAY-21	276
Screen	3	30	null	null