Max function repeat value [closed] - sql

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i am using below query to pick User highest qualification but i get repeated values. because user have more than one qualifications.
SELECT hrQualifications.Qualification,hrUserQualifications.HRUserID,MAX(hrQualifications.QualificationLevel) as Qlevel
FROM hrQualifications RIGHT OUTER JOIN
hrUserQualifications ON hrQualifications.QualificationID = hrUserQualifications.QualificationID RIGHT OUTER JOIN
hrUserApplyforPositions ON hrUserQualifications.HRUserID = hrUserApplyforPositions.HRUserID
WHERE (hrUserApplyforPositions.HrPositionID = 1)
group by hrQualifications.Qualification,hrUserQualifications.HRUserID
output which i got
Qualification UserID QualificationLevel
B.Sc.(Hons) 12 16
F.Sc 12 12
B.Sc.(Hons) 18 16
require output. i want highest qualification of user.
Qualification UserID QualificationLevel
B.Sc.(Hons) 12 16
B.Sc.(Hons) 18 16

Answer 1

A good way to do what you want is to use row_number(). This adds a sequential number to rows, starting over again within a partition and ordered by another field.
For your query:
with t as (
SELECT q.Qualification, uq.HRUserID, q.QualificationLevel as Qlevel,
row_number() over (partition by uq.HRUserID
order by q.QualificationLevel desc
) seqnum
FROM hrQualifications q RIGHT OUTER JOIN
hrUserQualifications uq
ON q.QualificationID = uq.QualificationID RIGHT OUTER JOIN
hrUserApplyforPositions uap
ON uq.HRUserID = uap.HRUserID
WHERE uap.HrPositionID = 1
)
select *
from t
where seqnum = 1;
Note that I also added table aliases to make the query more readable.