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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