How to only return 1 row when meet either subquery condition? - sql

Question

I work with electronic health records and need to determine % of patients who meet specific criteria. Note: Because the data is from EHR software, I don't have any control over how the tables and fields are organized.
My denominator is all patients who meet certain criteria, say PatientDenominator (for example: all patients who had XYZ123 service and were seen in July 2016 in a particular state). My numerator is how many in PatientDenominator had checkbox1 OR checkbox2 checked in the past year.
Except that these checkboxes are not evaluated at every visit - only at certain visits. So I have these as subqueries but because I put them in the FROM statement, when a patient meets both criteria they get two rows returned, which skews the numerator (which I'm doing in Excel for now since I'm still trying to figure out the query).
How do I reorganize the query so I can get only 1 row - when the patient meets EITHER criteria? The only way I see how is doing a CASE (when Scenario1 = 1 then 1 when Scenario2 = 1 then 1, else 0) but is that the best way to do it? I'm new to this sort of complexity and since I'll be evaluating many months at a time (and about 5,000 patients a month) I worry a little about performance.
declare
#startdate DATE,
#enddate DATE
set #startdate = '2016-07-01'
set #enddate = '2016-08-01'
select
PatientNumber,
PatientSex,
case
when (Scenario1='1' OR Scenario2='1') then 'Meets Criteria'
when (checkbox1 is null and checkbox2 is null) then 'N/A'
else 'Not Meet Criteria'
end 'Criteria'
from
PatientTable PT
left join VisitTable VT on PT.person_id=VT.person_id
left join LocationTable lt on VT.location_id=lt.location_id
left join TableZ on VT.VisitID=TableZ.VisitID
left join (
select distinct
PT1.person_id,
case
when TableA.checkbox1 = '1' OR TableB.checkbox2 = '1')
then '1'
else '0'
end Scenario1Eval
from
PatientTable1 PT1
left join VisitTable1 VT1 on PT1.person_id=VT1.person_id
left join TableA on VT1.VisitID=TableA.VisitID
left join TableB on VT1.VisitID=TableB.VisitID
left join TableC on VT1.VisitID=TableC.VisitID
where
sex='f'
and TableC.VisitType in ('Type1','Type2')
and (VT1.VisitDate > DATEADD(YEAR,-1,#startdate) and VT1.VisitDate < #enddate )
) as Scenario1 on PT.person_id=Scenario1.person_id
left join (
select distinct
PT2.person_id,
case
when TableA2.checkbox1 = '1' OR TableB2.checkbox2 = '1')
then '1'
else '0'
end Scenario2Eval
from
PatientTable1 PT2
left join VisitTable1 VT2 on PT2.person_id=VT2.person_id
left join TableA2 on VT2.VisitID=TableA2.VisitID
left join TableB2 on VT2.VisitID=TableB2.VisitID
left join TableD2 on VT2.VisitID=TableD2.VisitID
where
(VT1.VisitDate > DATEADD(YEAR,-1,#startdate) and VT1.VisitDate < #enddate )
and (TableD2.ChargeCode like '9920%' OR TableD2.ChargeCode like '9938%')) as Scenario2 on PT.person_id=Scenario2.person_id
where
VT1.VisitDate > #startdate and VT1.VisitDate < #enddate
and TableZ.QualifyingField = 'Y'
and lt.state='ZZ'
and (Scenario1 is not null OR Scenario2 is not null)