Hi again folks,
I am trying to calculate a sum of work-years based on database entries. In the end, for each employee, there should be displayed his total work-time in the department based on one or more employments.
basically, I tried it with THIS:
class WorkYearsManager(models.Manager):
def with_work_years(self):
today = datetime.date.today()
return self.annotate(
past_years=ExpressionWrapper(
(F('duty_end') - F('duty_begin')), output_field=fields.FloatField()
)/86400/365.2425/1000000*F('percent')/100
).annotate(
ongoing_years=ExpressionWrapper(
(today - F('duty_begin')), output_field=fields.FloatField()
)/86400/365.2425/1000000*F('percent')/100
)
def total_work_years(self, employee):
return self.with_work_years().filter(employee=employee).aggregate(
total_work_years=Sum('past_years') + Sum('ongoing_years')
)['total_work_years']
but of course, here will be calculatet the duty_end - duty_begin duration for EACH employment AND the today - duty_begin duration also for EACH employment…which leads to a way too large sum.
So, i need to restrict the ongoing_years calculation on the actual employment and the past_years calculation to all former employments…