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

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。

其他回答

使用Replace函数和FOR JSON PATH

SELECT T3.DEPT, REPLACE(REPLACE(T3.ENAME,'{"ENAME":"',''),'"}','') AS ENAME_LIST
FROM (
 SELECT DEPT, (SELECT ENAME AS [ENAME]
        FROM EMPLOYEE T2
        WHERE T2.DEPT=T1.DEPT
        FOR JSON PATH,WITHOUT_ARRAY_WRAPPER) ENAME
    FROM EMPLOYEE T1
    GROUP BY DEPT) T3

有关示例数据和更多方法,请点击这里

这类问题在这里经常被问到,解决方案将在很大程度上取决于潜在的需求:

https://stackoverflow.com/search?q=sql+pivot

and

https://stackoverflow.com/search?q=sql+concatenate

通常,如果没有动态sql、用户定义函数或游标,就没有仅使用sql的方法来完成此任务。

只是补充一下Cade所说的,这通常是一个前端显示的事情,因此应该在那里处理。我知道有时候100%用SQL编写文件导出或其他“仅SQL”解决方案更容易,但大多数时候这种连接应该在显示层中处理。

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

使用Sql Server 2005及以上版本的另一种选择

---- test data
declare @t table (OUTPUTID int, SCHME varchar(10), DESCR varchar(10))
insert @t select 1125439       ,'CKT','Approved'
insert @t select 1125439       ,'RENO','Approved'
insert @t select 1134691       ,'CKT','Approved'
insert @t select 1134691       ,'RENO','Approved'
insert @t select 1134691       ,'pn','Approved'

---- actual query
;with cte(outputid,combined,rn)
as
(
  select outputid, SCHME + ' ('+DESCR+')', rn=ROW_NUMBER() over (PARTITION by outputid order by schme, descr)
  from @t
)
,cte2(outputid,finalstatus,rn)
as
(
select OUTPUTID, convert(varchar(max),combined), 1 from cte where rn=1
union all
select cte2.outputid, convert(varchar(max),cte2.finalstatus+', '+cte.combined), cte2.rn+1
from cte2
inner join cte on cte.OUTPUTID = cte2.outputid and cte.rn=cte2.rn+1
)
select outputid, MAX(finalstatus) from cte2 group by outputid