Elegant way to make a SUm - oracle

Question

I need a query (in Oracle), that will be inside a stored procedure, where I can get a sum of the Amount value of Table REV.
The YEAR and one MONTH will be received as a parameter in the stored procedure, as YY and MM.
What I want is to sum the amount values since the 1st month of the year UP to the MM passed in the argument.
So
if MM in the argument is 02, I want to take the sum of amounts of months 01 + 02
if MM in the argument is 05, I want to take the sum of amounts of months 01+02+03+04+05
So MM is the last month to be summed.
How can I make this in the most efficient and elegant way?
CREATE OR REPLACE PROCEDURE "GET_YTD_AMOUNT" (YY in VARCHAR,
MM in VARCHAR)
select
ACT.LABEL ,
R.YEAR,
R.MONTH,
sum(R.AMOUNT)
from
ACTIVITY ACT,
REV R
where
R.YEAR=YEAR and
R.MONTH ??
R.ID_CODE = ACT.ID_CODE

Answer 1

I'd prefer using numeric variables rather than strings for such cases.
In your case ;
considering your year and month parameters are of string type, you need a to_number() conversion with less than or equal to operator
to_number(R.MONTH) <= to_number(i_month)
add an out parameter o_amount to return the result you get
of course, you need to convert your SQL format containing explicit
joins
better to define parameters ( or local variables ) by their type
within the tables in which they're contained. Btw, I didn't define o_amount by rev.amount%type against probability of sum() aggregation might exceed the precision of numeric value provided it's defined as so within the table.
So,use :
CREATE OR REPLACE PROCEDURE GET_YTD_AMOUNT(
i_year in rev.year%type,
i_month in rev.month%type,
o_amount out number
) IS
BEGIN
select sum(r.amount)
into o_amount
from activity a
join rev r
on r.id_code = a.id_code
where r.year = i_year
and to_number(r.month) <= to_number(i_month);
END;
/

Answer 2

You can use less than equal to:
select
ACT.LABEL ,
R.YEAR,
Max(R.MONTH) || '-' || Max(R.MONTH) as months_from_to
sum(R.AMOUNT)
from
ACTIVITY ACT,
REV R
where
R.YEAR= YY and -- it should be YY
R.MONTH <= MM -- less than equal to with MM
R.ID_CODE = ACT.ID_CODE
Group by ACT.LABEL ,
R.YEAR
Note: You must re-design your DB to store dates in date data type.
Cheers!!