Function 计算 2 个日期之间的天数，接受开始日期和结束日期，然后返回在该期间覆盖的天数

Question

I have to do something similar to this, and I need to spool file as well to css

CREATE OR REPLACE FUNCTION NumberOfDays
(in_date IN DATE)
RETURN NUMBER
IS
days NUMBER;
BEGIN
days:= TRUNC(SYSDATE - in_date);
EXCEPTION
WHEN OTHERS THEN
DBMS_OUTPUT.PUT_LINE(SQLERRM);
END;
/

Answer 1

Your sample code is almost there. You just need to add a second in parameter. Also, you need to return the result, so it gets back to the caller. Finally, there is no need for an intermediate variable. You can compute and return immediatly.

create or replace function number_of_days(start_date in date, end_date in date)
return number
is
begin
    return trunc(end_date - start_date);
exception
    when others then
    dbms_output.put_line(sqlerrm);
end;
/

Then you can do:

select number_of_days(date '2020-06-01', date '2020-06-06') res from dual

Yields:

| RES |
| --: |
|   5 |