Corelation between overtime and sick leave I have a scenario where I have to identify employees, who when take sick or any other paid leave his/her colleague (any other employee) gets overtime.

My data set is as follows:

employee_code----period---Leave_hours--- Overtime hours


How to identify the relation between overtime hours and leave_hours between employees?

Which machine learning model can be used to get employee wise relation...?
I don't see why you need a model at all.  This seems like a simple counting problem.  Here is SQL that finds pairs where one employee takes leave and another gets overtime:

select leave.employee_code, overtime.employee_code, count(*) as occurrences
from time_off leave
join time_off overtime
on leave.employee_id = overtime.employee_id 
   and leave.period = overtime.period
where leave.leave_hours &gt; 0
  and overtime.overtime_hours &gt; 0
group by leave.employee_code, overtime.employee_code
order by occurrences desc


In dplyr:

time_off %&gt;%
  filter(leave_hours &gt; 0) %&gt;%
  select(employee_code) %&gt;%
  inner_join(time_off %&gt;% 
               filter(overtime_hours) %&gt;%
               select(employee_code), 
             by=c("employee_code", "period"),
             suffix=c("_leave","_overtime")) %&gt;%
  group_by(employee_code_leave, employee_code_overtime) %&gt;%
  summarize(n=length(employee_code_leave)) %&gt;%
  arrange(desc(n))


Note that I haven't run this code, so it might have typos or bugs, but it should be close to correct.

To explore the relationship between leave hours and overtime hours, you don't even need the  employee pairs, you can just aggregate by period and make a scatter plot.