我如何得到:

id       Name       Value
1          A          4
1          B          8
2          C          9

to

id          Column
1          A:4, B:8
2          C:9

当前回答

不需要光标…while循环就足够了。

------------------------------
-- Setup
------------------------------

DECLARE @Source TABLE
(
  id int,
  Name varchar(30),
  Value int
)

DECLARE @Target TABLE
(
  id int,
  Result varchar(max) 
)


INSERT INTO @Source(id, Name, Value) SELECT 1, 'A', 4
INSERT INTO @Source(id, Name, Value) SELECT 1, 'B', 8
INSERT INTO @Source(id, Name, Value) SELECT 2, 'C', 9


------------------------------
-- Technique
------------------------------

INSERT INTO @Target (id)
SELECT id
FROM @Source
GROUP BY id

DECLARE @id int, @Result varchar(max)
SET @id = (SELECT MIN(id) FROM @Target)

WHILE @id is not null
BEGIN
  SET @Result = null

  SELECT @Result =
    CASE
      WHEN @Result is null
      THEN ''
      ELSE @Result + ', '
    END + s.Name + ':' + convert(varchar(30),s.Value)
  FROM @Source s
  WHERE id = @id

  UPDATE @Target
  SET Result = @Result
  WHERE id = @id

  SET @id = (SELECT MIN(id) FROM @Target WHERE @id < id)
END

SELECT *
FROM @Target

其他回答

使用Stuff和for xml路径操作符将行连接到字符串:Group By两列——>

CREATE TABLE #YourTable ([ID] INT, [Name] CHAR(1), [Value] INT)

INSERT INTO #YourTable ([ID],[Name],[Value]) VALUES (1,'A',4)
INSERT INTO #YourTable ([ID],[Name],[Value]) VALUES (1,'B',8)
INSERT INTO #YourTable ([ID],[Name],[Value]) VALUES (1,'B',5)
INSERT INTO #YourTable ([ID],[Name],[Value]) VALUES (2,'C',9)

-- retrieve each unique id and name columns and concatonate the values into one column
SELECT 
  [ID], 
  STUFF((
    SELECT ', ' + [Name] + ':' + CAST([Value] AS VARCHAR(MAX)) -- CONCATONATES EACH APPLICATION : VALUE SET      
    FROM #YourTable 
    WHERE (ID = Results.ID and Name = results.[name] ) 
    FOR XML PATH(''),TYPE).value('(./text())[1]','VARCHAR(MAX)')
  ,1,2,'') AS NameValues
FROM #YourTable Results
GROUP BY ID


SELECT 
  [ID],[Name] , --these are acting as the group by clause
  STUFF((
    SELECT ', '+  CAST([Value] AS VARCHAR(MAX)) -- CONCATONATES THE VALUES FOR EACH ID NAME COMBINATION 
    FROM #YourTable 
    WHERE (ID = Results.ID and Name = results.[name] ) 
    FOR XML PATH(''),TYPE).value('(./text())[1]','VARCHAR(MAX)')
  ,1,2,'') AS  NameValues
FROM #YourTable Results
GROUP BY ID, name

DROP TABLE #YourTable

如果你启用了clr,你可以使用GitHub中的Group_Concat库

如果是SQL Server 2017或SQL Server Vnext, SQL Azure,您可以使用STRING_AGG如下所示:

SELECT id, STRING_AGG(CONCAT(name, ':', [value]), ', ')
FROM #YourTable 
GROUP BY id

SQL Server 2005及其后续版本允许您创建自己的自定义聚合函数,包括像连接这样的功能—请参阅链接文章底部的示例。

一个例子是

在Oracle中可以使用LISTAGG聚合函数。

原始记录

name   type
------------
name1  type1
name2  type2
name2  type3

Sql

SELECT name, LISTAGG(type, '; ') WITHIN GROUP(ORDER BY name)
FROM table
GROUP BY name

导致

name   type
------------
name1  type1
name2  type2; type3