Question

My SQL is a little rusty and was just curious if there is a better way to do this WHERE clause? Assuming that there is a way, which I’m sure there is. It’s runs pretty quick as it is, but I just don’t like it and would like to know if it can be improved upon.

SELECT DISTINCT p.firstname              ,
            p.middlename             ,
            p.lastname               ,
            p.gender                 ,
            p.dob                    ,
            p.id      AS patientid   ,
            pr.id     AS practiceid  ,
            pr.[name] AS practicename,
            pr.parentaco             ,
            pp.encounterdate
FROM            ((aco.patients_practices patients_practices
            LEFT OUTER JOIN aco.patients p
            ON              (
                             patients_practices.patientid = p.id
                            )
            )
            LEFT OUTER JOIN aco.practices pr
            ON              (
                             patients_practices.practiceid = pr.id
                            )
            )
            INNER JOIN aco.patientpreferences pp
            ON              (
                             pp.patientid = p.id
                            )
WHERE           (
                            pr.parentaco =
                            (SELECT parentaco
                            FROM    aco.practices
                            WHERE   master_companyid = 763
                            )
            OR              pr.id =
                            (SELECT parentaco
                            FROM    aco.practices
                            WHERE   master_companyid = 763
                            )
            )
AND             pp.encounterdate IS NOT NULL

Answer 1

You could fetch the value from you sub-query first and put it in variable.

DECLARE @P INT

SELECT @P = parentaco
FROM aco.practices
WHERE master_companyid = 763

Use the variable in the query

WHERE (pr.parentaco = @P or pr.id = @P) AND
      pp.encounterdate IS NOT NULL