如何识别新值

Question

我有 3 个 table 相互连接以获取我的客户的信息。我的一些客户是多种族的，这使得 table 有重复的行。我想知道我是否可以识别一个新值并说如果 ID 重复，在比赛中给我多种族作为值？
我有这个：

ID     Name     Age   Race
4000    Duc      25    Philipino
4000    Duc      25    Chinese
4001    Daniel   36    African American
4002    Nicole   20    White
4002    Nicole   20    Middle East

我想要这个

ID      Name      Age    Race
4000    Duc       25     Multiracial
4001    Daniel    36     African American
4002    Nicole    20     Multiracial

非常感谢任何帮助

Answer 1

;WITH CTE
AS
(SELECT ID,NAME,AGE,RACE,COUNT(*) OVER (PARTITION BY ID,NAME,AGE ORDER BY (SELECT NULL)) AS CNT
FROM
#TEMP
)
SELECT ID,NAME,AGE,CASE WHEN CNT>1 THEN 'MULTIRACILA' ELSE RACE END
FROM CTE
GROUP BY 
ID,NAME,AGE,CASE WHEN CNT>1 THEN 'MULTIRACILA' ELSE RACE END

Answer 2

你可以做到（应该适用于 MS SQL 和 MySQL）：

SELECT ID,Name,Age, CASE WHEN COUNT(Race)>1 THEN 'Mulitiracial' ELSE MAX(Race) END Race
FROM Src
GROUP BY ID,Name,Age

为了测试您的数据（CTE 仅在 MS SQL）我使用了以下内容：

WITH Src AS
(
    SELECT * FROM (VALUES
    (4000, 'Duc   ', 25, 'Philipino'        ),
    (4000, 'Duc   ', 25, 'Chinese'          ),
    (4001, 'Daniel', 36, 'African American' ),
    (4002, 'Nicole', 20, 'White           ' ),
    (4002, 'Nicole', 20, 'Middle East     ' )
    )T (ID,Name,Age,Race)
)
SELECT ID,Name,Age, CASE WHEN COUNT(Race)>1 THEN 'Mulitiracial' ELSE MAX(Race) END Race
FROM Src
GROUP BY ID,Name,Age

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