Oracle SQL中的连续记录

Question

I have a similar question thought to post here. Need Employees who were absent for 3 or more consecutive days. Assume all the days are working days no holidays on Saturday/Sunday/Anyother days.

In the table below I need 20342123 and 20311111 in the result set. Employee 20311333 has taken 4 leaves but they are not consecutive.

Thanks for help in advance.

Emp Id     |  AsofDate      | Comment 
----------------------------------
20342123   |  1-JAN-2017| Absent 
20342123   |  2-JAN-2017| Absent 
20342123   |  3-JAN-2017| Absent
20311111   |  1-JAN-2017| Absent 
20311111   |  2-JAN-2017| Absent 
20311111   |  3-JAN-2017| Absent
20311333   |  5-JAN-2017| Absent
20311333   |  6-JAN-2017| Absent
20311333   |  8-JAN-2017| Absent 
20311333   |  9-JAN-2017| Absent
20322222   |  1-JAN-2017| Absent
20322222   |  2-JAN-2017| Absent

Answer 1

Although you can apply a "gaps-and-islands" solution, I think lag() / lead() is simpler for this problem:

select distinct emp_id
from (select t.*,
             lead(date) over (partition by empid order by date) as date_1,
             lead(date, 2) over (partition by empid order by date) as date_2
      from t
      where comment = 'Absent'  -- not sure if this is important
     ) t
where date_1 = date + 1 and date_2 = date + 2;