利用FOR XML PATH行转列（根据某字段分组，多行数据转成一行，并用逗号隔开）

CREATE TABLE #TEST
(A VARCHAR(10) NULL,B VARCHAR(MAX) NULL)

INSERT INTO #TEST
SELECT ‘A‘,‘A001‘
UNION ALL
SELECT ‘A‘,‘A002‘
UNION ALL
SELECT ‘A‘,‘A003‘
UNION ALL
SELECT ‘B‘,‘B001‘
UNION ALL
SELECT ‘B‘,‘B002‘

SELECT * FROM #TEST

--先来看一个简单的，效果如下图所示：

SELECT STUFF((SELECT ‘,‘+B FROM #TEST FOR XML PATH(‘‘)),1,1,‘‘)

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--再来个我们想要的，效果见下图：
SELECT DISTINCT t1.A,
REPLACE((SELECT B AS [data()] FROM #TEST t2 WHERE t1.A=t2.A FOR XML PATH(‘‘)),‘ ‘,‘,‘) AS B
FROM #TEST t1

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原文地址：https://www.cnblogs.com/lrl45/p/12001108.html