Unable to use aggregate function in value set

Summary

Need to use SUM Function in value set

Content

I have created Value set but i need to use the sum function in it but error out. I think there is some limitation. Please see the below or you guys can suggest DB items.

 

Select a.DURATION  from ANC_PER_ABS_ENTRIES a , PER_ALL_PEOPLE_F P , PER_ALL_ASSIGNMENTS_F F

WHERE a.ABSENCE_TYPE_ID = 300000002435648

AND p.person_id = a.person_id

AND F.person_id = p.person_id

AND F.EMPLOYMENT_CATEGORY = 'PERPM'

AND p.person_id = :{PARAMETER.p_emp_id}