Question

我使用以下查询来选择用户最高资格，但我得到重复的值。因为用户有多个资格。

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

我得到的输出

Qualification    UserID      QualificationLevel
B.Sc.(Hons)        12        16
    F.Sc           12        12
B.Sc.(Hons)        18        16

需要输出。我想要最高的用户资格。

Qualification    UserID      QualificationLevel
B.Sc.(Hons)        12            16   
B.Sc.(Hons)        18            16

Answer 1

执行所需操作的好方法是使用row_number()。这会向行添加一个序列号，在分区内重新开始并按另一个字段排序。

查询：

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;

请注意，我还添加了表别名以使查询更具可读性。

最大功能重复值

1 个答案: