Calculate business days in Oracle SQL(no functions or procedure)

Question

I am trying to calculate business days between two dates in Oracle select. I got to the point when my calculation gives most results correct for given dates (I compare it with NETWORKDAYS in excel) but sometimes it varies from 2 days to -2 days - and I don't know why...

Here's my code:

SELECT
((to_char(CompleteDate,'J') - to_char(InstallDate,'J'))+1) - (((to_char(CompleteDate,'WW')+ (52 * ((to_char(CompleteDate,'YYYY') - to_char(InstallDate,'YYYY'))))) - to_char(InstallDate,'WW'))*2) as BusinessDays
FROM TABLE

Thanks!

Answer 1

The solution, finally:

SELECT OrderNumber, InstallDate, CompleteDate,
  (TRUNC(CompleteDate) - TRUNC(InstallDate) ) +1 - 
  ((((TRUNC(CompleteDate,'D'))-(TRUNC(InstallDate,'D')))/7)*2) -
  (CASE WHEN TO_CHAR(InstallDate,'DY','nls_date_language=english')='SUN' THEN 1 ELSE 0 END) -
  (CASE WHEN TO_CHAR(CompleteDate,'DY','nls_date_language=english')='SAT' THEN 1 ELSE 0 END) as BusinessDays
FROM Orders
ORDER BY OrderNumber;

Thanks for all your responses !

Answer 2

Try this:

with holidays as 
(
select d from (
select minDate + level -1 d
 from (select min(submitDate) minDate, max (completeDate) maxDate
 from t)
 connect by level <= maxDate - mindate + 1) 
 where to_char(d, 'dy', 'nls_date_language=AMERICAN') not in ('sun' , 'sat')
)
select t.OrderNo, t.submitDate, t.completeDate, count(*) businessDays
from t join holidays h on h.d between t.submitDate and t.completeDate
group by t.OrderNo, t.submitDate, t.completeDate
order by orderno

Here is a sqlfiddle demo

Answer 3

I took into account all the different approaches discussed above and came up with a simple query that gives us the number of working days in each month of the year between two dates:

WITH test_data AS ( SELECT TO_DATE('01-JAN-14') AS start_date, TO_DATE('31-DEC-14') AS end_date
FROM dual ), all_dates AS (
SELECT td.start_date, td.end_date, td.start_date + LEVEL-1 as week_day FROM test_data td CONNECT BY td.start_date + LEVEL-1 <= td.end_date) SELECT TO_CHAR(week_day, 'MON'), COUNT(*)
FROM all_dates WHERE to_char(week_day, 'dy', 'nls_date_language=AMERICAN') NOT IN ('sun' , 'sat') GROUP BY TO_CHAR(week_day, 'MON');

Please feel free to modify the query as needed.

Answer 4

I changed my example to more readable and to return count of bus. days between. I do not know why you need 'J'- Julian format. All it takes is start/Install and end/Complete dates. You will get correct number of days between 2 dates using this. Replace my dates with yours, add NLS if needed...:

 SELECT Count(*) BusDaysBtwn
  FROM
  (
  SELECT TO_DATE('2013-02-18', 'YYYY-MM-DD') + LEVEL-1 InstallDate  -- MON or any other day 
       , TO_DATE('2013-02-25', 'YYYY-MM-DD') CompleteDate           -- MON or any other day
       , TO_CHAR(TO_DATE('2013-02-18', 'YYYY-MM-DD') + LEVEL-1, 'DY') InstallDay   -- day of week
    FROM dual 
  CONNECT BY LEVEL <= (TO_DATE('2013-02-25', 'YYYY-MM-DD') - TO_DATE('2013-02-18', 'YYYY-MM-DD')) -- end_date - start_date 
   )
   WHERE InstallDay NOT IN ('SAT', 'SUN')
  /

  SQL> 5