Calculating Business Days(Start_dt - End_dt)

Question

Hi Friends,
Could anyone of you help me to find out the business days(Excluding Saturdays and Sundays) between two dates.
The difference should be calculated of both the Start_dt and End_dt values truncated. The result should be calculated and stored according to business days, it means weekend days are to be ignored.
create table sample (id number,start_dt date,end_dt date). The table values are as follows;
ID ; start_dt ; End_dt
1 ; 08-02-2012 ; 15-02-2012
2 ; 30-12-2011 ; 15-02-2012
My output should be;
ID ; start_dt ; End_dt ; Expected Business Days (Excluding Weekends)
1 ; 08-02-2012 ; 15-02-2012 ; 4
2 ; 30-12-2011 ; 15-02-2012 ; 33
Please note that, the Start Date and End Date can be any date from any year. Please help me on this.
Regards,
Williams.
Edited by: Williams on Feb 8, 2012 6:28 PM
Edited by: Williams on Feb 8, 2012 6:29 PM

Answer 1

Here's my first cut at it.
SQL> WITH sample AS
  2  (
  3     SELECT 1 AS id, TO_DATE('08-02-2012','DD-MM-YYYY') AS start_dt, TO_DATE('15-02-2012','DD-MM-YYYY') AS end_dt FROM DUAL UNION ALL
  4     SELECT 2 AS id, TO_DATE('30-12-2011','DD-MM-YYYY') AS start_dt, TO_DATE('15-02-2012','DD-MM-YYYY') AS end_dt FROM DUAL
  5  )
  6  /* END SAMPLE DATA */
  7  SELECT id
  8       , start_dt
  9       , end_dt
10       , COUNT(*)
11  FROM   sample
12  JOIN   ( /* Exclude Weekends */
13           SELECT dt
14           FROM  ( /* Generate a range that includes all days */
15                   SELECT min_start_dt + (LEVEL - 1) AS dt
16                        , TO_CHAR
17                          ( min_start_dt + (LEVEL - 1)
18                          , 'fmDAY'
19                          , 'NLS_DATE_LANGUAGE=AMERICAN'
20                          ) AS dy
21                   FROM   ( SELECT MIN(start_dt) AS min_start_dt
22                                 , MAX(end_dt)   AS max_end_dt
23                            FROM   sample
24                          )
25                   CONNECT BY LEVEL <= max_end_dt - min_start_dt + 1
26                 )
27           WHERE dy NOT IN ('SATURDAY','SUNDAY')
28         ) dys ON dys.dt BETWEEN start_dt AND end_dt
29  GROUP BY id
30         , start_dt
31         , end_dt
32  /
        ID START_DT            END_DT                COUNT(*)
         2 12/30/2011 00:00:00 02/15/2012 00:00:00         34
         1 02/08/2012 00:00:00 02/15/2012 00:00:00          6
2 rows selected.I got different results then you though. Can you say why your counts are what they are?