Query works but not in a funtion

Question

i have this query... select sum(amount) from here and there where id=myid and mydate =desireddate... works flawlessly...
but when i put this query in a function and pass on the parameters does not work... function looks like this.....
create or replace function myfunction(myid varchar2, desired date) return number is
amount number;
begin
here goes query...where id=myid and mydate=desireddate;
return amount ;
end;
It seems something about the mydesireddate parameter, cause when i manually put the value works fine....currently function returns all mydate rows, i just want mydesired date rows.
thanks in advance....

Answer 1

currently function returns all mydate rows, i just want mydesired date rowsCheck if there is a column in the table with the same name as the function parameter. It's the most probable reason of such DML operations behaviour in PL/SQL procedures and function.
Rgds.