SQLSERVER中的ListAGG

Question

我正在嘗試聚合SQLServer中的「STRING」字段。我想在Oracle中找到與LISTAGG相同的函數。

你知道如何做同樣的功能或其他方法嗎？

例如，

Field A | Field B 
1  | A 
1  | B 
2  | A 

而且我想這個查詢的結果將是

1 | AB 
2 | A 

Answer 1

在SQL Server，你可以使用FOR XML PATH得到結果：

select distinct t1.FieldA, 
    STUFF((SELECT distinct '' + t2.FieldB 
     from yourtable t2 
     where t1.FieldA = t2.FieldA 
      FOR XML PATH(''), TYPE 
      ).value('.', 'NVARCHAR(MAX)') 
     ,1,0,'') data 
from yourtable t1; 

請參閱SQL Fiddle with Demo

Answer 2

在sqlserver的：

SELECT FieldA , STUFF((SELECT ','+ FieldB FROM TableName a 
WHERE b.FieldA = a.FieldA FOR XML PATH('')),1 ,1, '') Members 
FROM TableName b 
GROUP BY FieldA; 

在MySQL：

SELECT FieldA, GROUP_CONCAT(FieldB) AS Members 
FROM TableName 
GROUP BY FieldA 
ORDER BY FieldA; 

在Oracle：

SELECT FieldA, LISTAGG(FieldB, ',') WITHIN GROUP (ORDER BY FieldA) AS Members 
FROM TableName 
GROUP BY FieldA; 

Answer 3

在SQL Server 2017​​增加：

SELECT t.name,STRING_AGG (c.name, ',') AS csv 
FROM sys.tables t 
JOIN sys.columns c on t.object_id = c.object_id 
GROUP BY t.name 
ORDER BY 1 

此外，STRING_SPLIT是有用的相反的情況，並提供在SQL Server 2016