mysql-function to count days between 2 dates excluding weekends - mysql

Question

I've searched through many examples , good ones I got :
Count days between two dates, excluding weekends (MySQL only)
How to count date difference excluding weekend and holidays in MySQL
Calculate diffference between 2 dates in SQL, excluding weekend days
but didn't get most promising solution , so that i can use in my mysql-function for quering lakhs of rows.
This one was very new concept , but didn't worked for inputs like #start_date = '2013-08-03' , #end_date = '2013-08-21' Expected ans : 13 , its giving only 12,
SELECT 5 * (DATEDIFF(#end_date, #start_date) DIV 7) + MID('0123444401233334012222340111123400012345001234550', 7 * WEEKDAY(#start_date) + WEEKDAY(#end_date) + 1, 1);
So i'did tried to make it by myself -
Concept :
Input : 1. period_from_date - from date
2. period_to_date - to date
3. days_to_exclude - mapping : S M T W TH F Sat => 2^0 + 2^6
(sat and sun to exclude) ^ ^ ^ ^ ^ ^ ^
0 1 2 3 4 5 6
DELIMITER $$
USE `db_name`$$
DROP FUNCTION IF EXISTS `FUNC_CALC_TOTAL_WEEKDAYS`$$
CREATE DEFINER=`name`#`%` FUNCTION `FUNC_CALC_TOTAL_WEEKDAYS`( period_from_date DATE, period_to_date DATE, days_to_exclude INT ) RETURNS INT(11)
BEGIN
DECLARE period_total_num_days INT DEFAULT 0;
DECLARE period_total_working_days INT DEFAULT 0;
DECLARE period_extra_days INT DEFAULT 0;
DECLARE period_complete_weeks INT DEFAULT 0;
DECLARE extra_days_start_date DATE DEFAULT '0000-00-00';
DECLARE num_days_to_exclude INT DEFAULT 0;
DECLARE start_counter_frm INT DEFAULT 0;
DECLARE end_counter_to INT DEFAULT 6;
DECLARE temp_var INT DEFAULT 0;
# if no day to exclude return date-diff only
IF days_to_exclude = 0 THEN
RETURN DATEDIFF( period_to_date, period_from_date ) + 1 ;
END IF;
# get total no of days to exclude
WHILE start_counter_frm <= end_counter_to DO
SET temp_var = POW(2,start_counter_frm) ;
IF (temp_var & days_to_exclude) = temp_var THEN
SET num_days_to_exclude = num_days_to_exclude + 1;
END IF;
SET start_counter_frm = start_counter_frm + 1;
END WHILE;
# Get period days count
SET period_total_num_days = DATEDIFF( period_to_date, period_from_date ) + 1 ;
SET period_complete_weeks = FLOOR( period_total_num_days /7 );
SET period_extra_days = period_total_num_days - ( period_complete_weeks * 7 );
SET period_total_working_days = period_complete_weeks * (7 - num_days_to_exclude);
SET extra_days_start_date = DATE_SUB(period_to_date,INTERVAL period_extra_days DAY);
# get total working days from the left days
WHILE period_extra_days > 0 DO
SET temp_var = DAYOFWEEK(period_to_date) -1;
IF POW(2,temp_var) & days_to_exclude != POW(2,temp_var) THEN
SET period_total_working_days = period_total_working_days +1;
END IF;
SET period_to_date = DATE_SUB(period_to_date,INTERVAL 1 DAY);
SET period_extra_days = period_extra_days -1;
END WHILE;
RETURN period_total_working_days;
END$$
DELIMITER ;
Please let me know the holes where this would fail.Open to any suggestions and comments.

Answer 1

UPDATED: If you just need a number of weekdays between two dates you can get it like this
CREATE FUNCTION TOTAL_WEEKDAYS(date1 DATE, date2 DATE)
RETURNS INT
RETURN ABS(DATEDIFF(date2, date1)) + 1
- ABS(DATEDIFF(ADDDATE(date2, INTERVAL 1 - DAYOFWEEK(date2) DAY),
ADDDATE(date1, INTERVAL 1 - DAYOFWEEK(date1) DAY))) / 7 * 2
- (DAYOFWEEK(IF(date1 < date2, date1, date2)) = 1)
- (DAYOFWEEK(IF(date1 > date2, date1, date2)) = 7);
Note: The function will still work if you switch start date1 and end date2 dates.
Sample usage:
SELECT TOTAL_WEEKDAYS('2013-08-03', '2013-08-21') weekdays1,
TOTAL_WEEKDAYS('2013-08-21', '2013-08-03') weekdays2;
Output:
| WEEKDAYS1 | WEEKDAYS2 |
-------------------------
| 13 | 13 |
Here is DBFiddle demo

Answer 2

This query will work fine, all the queries above are not working well. Try this :
SELECT ((DATEDIFF(date2, date1)) -
((WEEK(date2) - WEEK(date1)) * 2) -
(case when weekday(date2) = 6 then 1 else 0 end) -
(case when weekday(date1) = 5 then 1 else 0 end)) as DifD
Test it like this :
SELECT ((DATEDIFF('2014-10-25', '2014-10-15')) -
((WEEK('2014-10-25') - WEEK('2014-10-15')) * 2) -
(case when weekday('2014-10-25') = 6 then 1 else 0 end) -
(case when weekday('2014-10-15') = 5 then 1 else 0 end)) as DifD
The result :
DifD
8

Answer 3

I use this. Means there are no functions so can be used in views:
select
datediff(#dateto, #datefrom) +
datediff(#datefrom,
date_add(#datefrom, INTERVAL
floor(datediff(#dateto, #datefrom) / 7) day)) * 2
- case
when weekday(#dateto) = 6 then 2
when weekday(#dateto) = 5 then 1
when weekday(#dateto) < weekday(#datefrom) then 2
else 0
end;

Answer 4

Had a similar issue, I used PHP to remove the weekends, need to know start day and number of days:
EG SQL:
SELECT DAYOFWEEK(`date1`) AS `startday`, TIMESTAMPDIFF(DAY, `date1`, `date2`) AS `interval` FROM `table`
Then run the result through a PHP function:
function noweekends($startday, $interval) {
//Remove weekends from an interval
$wecount = 0; $tmp = $interval;
while($interval/7 > 1) { $interval-=7; $wecount++; }
if($interval+$startday > 5) $wecount++;
$interval = $tmp-($wecount*2);
return $interval;
}

Answer 5

To exclude only Sunday:
CREATE FUNCTION TOTAL_WEEKDAYS(date1 DATE, date2 DATE)
RETURNS INT
RETURN ABS(DATEDIFF(date2, date1)) + 1
- ABS(DATEDIFF(ADDDATE(date2, INTERVAL 1 - DAYOFWEEK(date2) DAY),
ADDDATE(date1, INTERVAL 1 - DAYOFWEEK(date1) DAY))) / 7
- (DAYOFWEEK(IF(date1 < date2, date1, date2)) = 1);

Answer 6

You can also create triggers to automatically calculate it in another column, and you can specify legal holidays in another table:
CREATE OR REPLACE TRIGGER `vacation_before_insert` BEFORE INSERT ON `vacation` FOR EACH ROW
BEGIN
SET #start_date = NEW.Start_date;
SET #end_date = NEW.End_date;
SET #numofholydays = (IFNULL((SELECT SUM(IF(`Date` BETWEEN NEW.Start_date AND NEW.End_date, 1, 0)) as numofdays FROM free_legal_days),0));
SET #totaldays = DATEDIFF(#end_date , #start_date) + 1;
SET #saturdays = WEEK(DATE_ADD(#end_date, INTERVAL 1 DAY))-WEEK(#start_date);
SET #sundays = WEEK(#end_date) - WEEK(#start_date);
SET NEW.Number_of_days = #totaldays-#saturdays-#sundays-#numofholydays;
END;
CREATE OR REPLACE TRIGGER `vacation_before_update` BEFORE UPDATE ON `vacation` FOR EACH ROW
BEGIN
SET #start_date = NEW.Start_date;
SET #end_date = NEW.End_date;
SET #numofholydays = (IFNULL((SELECT SUM(IF(`Date` BETWEEN NEW.Start_date AND NEW.End_date, 1, 0)) as numofdays FROM free_legal_days),0));
SET #totaldays = DATEDIFF(#end_date , #start_date) + 1;
SET #saturdays = WEEK(DATE_ADD(#end_date, INTERVAL 1 DAY))-WEEK(#start_date);
SET #sundays = WEEK(#end_date) - WEEK(#start_date);
SET NEW.Number_of_days = #totaldays-#saturdays-#sundays-#numofholydays;
END;