openmrs sql dataset

select pa.value as Direction, round((count(*)*100/totalagent)) as Pourcentage
from visit v, person_attribute pa, (select count(*) as totalagent from patient where
 voided!= "1") as c
where v.voided != "1"
and v.date_started >= :startDate
and v.date_started <= :endDate
and pa.person_attribute_type_id = "13"
and v.patient_id = pa.person_id
and pa.voided != "1"

group by Direction