Question

I have a T-SQL query that’s giving me the most recent office visit in 2010 that wasn’t a dental visit. The relevant part of the query is:

AND pv.PatientVisitId IN (                
    SELECT Max(pv1.PatientVisitID)            
        FROM PatientVisit pv1        
            JOIN DoctorFacility df1 ON pv1.FacilityID = df1.DoctorFacilityID
            JOIN PatientVisitResource pvr1 ON pv1.PatientVisitId = pvr1.PatientVisitId
                JOIN DoctorFacility dfr ON pvr1.ResourceId = dfr.DoctorFacilityId
        WHERE pv1.PatientProfileID = pp.PatientProfileID        
            AND pv1.Visit < '2011-01-01'    
            AND df1.ListName NOT LIKE '%Dental%'    
    )  

Now, I want to flip that around to get the most recent office visit for the patients who only had dental appointments. I keep hitting the wall here, though. Can anyone bust me through to the other side? 🙂

Answer 1

The clue is to use where not exists

AND pv.PatientVisitId IN (                
    SELECT Max(pv1.PatientVisitID)            
        FROM PatientVisit pv1        
            JOIN DoctorFacility df1 ON pv1.FacilityID = df1.DoctorFacilityID
            JOIN PatientVisitResource pvr1 ON pv1.PatientVisitId = pvr1.PatientVisitId
                JOIN DoctorFacility dfr ON pvr1.ResourceId = dfr.DoctorFacilityId
        WHERE pv1.PatientProfileID = pp.PatientProfileID        
            AND pv1.Visit < '2011-01-01'    
            AND df1.ListName LIKE '%Dental%'    
    ) 
and not exists ( Select 1 from   PatientVisit pv1        
            JOIN DoctorFacility df1 ON pv1.FacilityID = df1.DoctorFacilityID
            JOIN PatientVisitResource pvr1 ON pv1.PatientVisitId = pvr1.PatientVisitId
                JOIN DoctorFacility dfr ON pvr1.ResourceId = dfr.DoctorFacilityId
        WHERE pv1.PatientProfileID = pp.PatientProfileID        
            AND pv1.Visit < '2011-01-01'    
            AND df1.ListName NOT LIKE '%Dental%'    
    )