sql - 用逗号分隔的单个字段中的多行 SQL Server

Question

可能重复：
在 MS SQL Server 2005 中模拟 group_concat MySQL 函数？

实现此结果的 SQL Server 代码是什么：

SO number  Line number            
123           6
123          189
456           34

需要输出：

SO number  Line number 
 123            6,189
 456               34   

Answer 1

尝试这个 ：-

CREATE TABLE #Sample ([SO Number] INT, [Line Number] INT)

INSERT INTO #Sample ([SO Number],[Line Number]) VALUES (123,6)
INSERT INTO #Sample ([SO Number],[Line Number]) VALUES (123,189)
INSERT INTO #Sample ([SO Number],[Line Number]) VALUES (456,34)


SELECT ID,
STUFF((
SELECT ', ' + cast([Line Number] as varchar(max) )
FROM #Sample 
WHERE ([SO Number] = a.[SO Number]) 
FOR XML PATH (''))
,1,2,'') AS b
FROM #Sample a
GROUP BY [SO Number]

编辑 ：

XML PATH (''):Is used to retrieve the column values seperated by comma 
Ex:- ,6,189,34

STUFF：用于将一个字符串插入到另一个字符串中。表达式为

STUFF ( character_expression , start , length ,character_expression )

起始长度为 1，因为我们必须替换 XML PATH 创建的第一个逗号。''插入的空间长度为 1

因此，即使您有 20K 行，表达式仍将与 1,2 用于插入空间相同

Answer 2

DECLARE @Sample Table([SO Number] INT, [Line Number] INT)

INSERT INTO @Sample ([SO Number],[Line Number]) VALUES (123,6)
INSERT INTO @Sample ([SO Number],[Line Number]) VALUES (123,189)
INSERT INTO @Sample ([SO Number],[Line Number]) VALUES (456,34)

select * from @Sample

select [SO Number],STUFF((select ','+cast([Line Number] as varchar(100)) from  @Sample s1 where s1.[SO Number] =s.[SO Number]  FOR XML path('')),1,1,'' )  as [Line Number]     from  @Sample s
group by [SO Number]