INTCK Weekday

[Kraj1989]

data test2;
weekdays=intck('Weekday','01May2019'd,'18May2019'd);
run;

it suppose to give me 13 days but giving 12 days, Any one know why it is giving 12 days

[Astounding]

INTCK counts the number of boundaries crossed.  It does not count May 1, in your example.  The first "crossing" is the boundary from May 1 to May 2.

[PGStats]

Look at this little test:

50   data _null_;
51   fromDate = '01May2019'd;
52   do toDate = fromDate to '18May2019'd;
53       weekdays=intck('Weekday', fromDate, toDate);
54       put fromDate downame. +1  fromDate yymmdd10. +1
55           toDate downame. +1    toDate yymmdd10. +1
56           weekDays;
57       end;
58   run;

Wednesday 2019-05-01 Wednesday 2019-05-01 0
Wednesday 2019-05-01  Thursday 2019-05-02 1
Wednesday 2019-05-01    Friday 2019-05-03 2
Wednesday 2019-05-01  Saturday 2019-05-04 2
Wednesday 2019-05-01    Sunday 2019-05-05 2
Wednesday 2019-05-01    Monday 2019-05-06 3
Wednesday 2019-05-01   Tuesday 2019-05-07 4
Wednesday 2019-05-01 Wednesday 2019-05-08 5
Wednesday 2019-05-01  Thursday 2019-05-09 6
Wednesday 2019-05-01    Friday 2019-05-10 7
Wednesday 2019-05-01  Saturday 2019-05-11 7
Wednesday 2019-05-01    Sunday 2019-05-12 7
Wednesday 2019-05-01    Monday 2019-05-13 8
Wednesday 2019-05-01   Tuesday 2019-05-14 9
Wednesday 2019-05-01 Wednesday 2019-05-15 10
Wednesday 2019-05-01  Thursday 2019-05-16 11
Wednesday 2019-05-01    Friday 2019-05-17 12
Wednesday 2019-05-01  Saturday 2019-05-18 12

Note that weekends are lumped with Fridays in the counting of weekdays.