使用 Rank Over Partition 查找重复项 [英] Find Duplicates using Rank Over Partition

问题描述

当 LastDate 存在差异时，以下 SQL 可用于识别唯一电话.但如果重复的手机具有完全相同的 LastDate，则它不起作用.

The following SQL works in identifying unique phones when there is a disparity in LastDate. But if duplicate phones have the exact same LastDate it does not work.

任何想法将不胜感激.

SELECT * FROM
 (
  SELECT  ID, Phone, [LastDate]
  ,RANK() OVER (PARTITION BY Phone ORDER BY [LastDate]) AS 'RANK',                          
            COUNT(Phone) OVER (PARTITION BY  Phone) AS 'MAXCOUNT'
              FROM MyTable          
              WHERE Groupid = 5
              ) a
              WHERE [RANK] = [MAXCOUNT] 

推荐答案

更改 ROW_NUMBER 的 RANK.

SELECT * 
FROM  (   SELECT    ID, Phone, [LastDate],
                    ROW_NUMBER() OVER (PARTITION BY Phone ORDER BY [LastDate]) AS 'RANK',
                    COUNT(Phone) OVER (PARTITION BY  Phone) AS 'MAXCOUNT'
          FROM MyTable
          WHERE Groupid = 5) a 
WHERE [RANK] = [MAXCOUNT]

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