How to avoid multiple rows from a join query? - sql

Question

Below is my SQL query. If the fbkWeightMaster has multiple records for the same patient, it returns multiple rows in the result. I want to avoid it. I tried using Distinct, but did not work.
I confirmed that the issue occurs when there are multiple entries in fbkWeightMaster table from the below query.
Select Distinct
a.patientid
, a.firstname
, a.lastname
, a.mobile
, a.dob
, b.InitialWeight
, b.LatestWeight
, a.height
, c.PlanName
, a.warning
, a.indicator
, a.city
, a.email
, a.state
, a.comments
, a.introduction
, a.gender
, a.address
, a.landline
, a.FoodPreference
From
fbkPatientMaster a
Join
fbkPlanMaster c On a.PlanID = c.PlanID
Join
fbkWeightMaster b On a.PatientID = b.PatientID
Join
fbkChartMaster d On d.PatientID = a.PatientID
Where
IsActive = 1
And a.PatientID Not In (Select Distinct PatientID
From fbkChartMaster
Where Cast(ChartDate As Date) = DateAdd(Day, 1, Cast(GetDate() As Date)))
And a.PatientID Not In (Select Distinct PatientID
From fbkChartHold
Where Cast(ChartHoldTo As Date) > Cast(GetDate() As Date));

Answer 1

You could change your join to a cross apply() and select top 1 from fbkWeightMaster according to some order, such as a date column. This will return only 1 row from fbkWeightMaster per a.patientid.
cross apply() works similar to an inner join if you want the functionality you get with a left join use outer apply() instead.
Select
a.patientid
, a.firstname
, a.lastname
, a.mobile
, a.dob
, b.InitialWeight
, b.LatestWeight
, a.height
, c.PlanName
, a.warning
, a.indicator
, a.city
, a.email
, a.state
, a.comments
, a.introduction
, a.gender
, a.address
, a.landline
, a.FoodPreference
From
fbkPatientMaster a
Join
fbkPlanMaster c On a.PlanID = c.PlanID
Join
fbkChartMaster d On d.PatientID = a.PatientID
cross apply (
select top 1 *
from fbkWeightMaster b
where a.PatientID = b.PatientID
order by b.date desc
) b
Where
IsActive = 1
And a.PatientID Not In (Select Distinct PatientID
From fbkChartMaster
Where Cast(ChartDate As Date) = DateAdd(Day, 1, Cast(GetDate() As Date)))
And a.PatientID Not In (Select Distinct PatientID
From fbkChartHold
Where Cast(ChartHoldTo As Date) > Cast(GetDate() As Date));