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
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
不需要游标,WHILE循环或用户定义函数。
只需要创造性地使用FOR XML和PATH。
[注意:此解决方案仅适用于SQL 2005及更高版本。原来的问题没有指定使用的版本。
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 (2,'C',9)
SELECT
[ID],
STUFF((
SELECT ', ' + [Name] + ':' + CAST([Value] AS VARCHAR(MAX))
FROM #YourTable
WHERE (ID = Results.ID)
FOR XML PATH(''),TYPE).value('(./text())[1]','VARCHAR(MAX)')
,1,2,'') AS NameValues
FROM #YourTable Results
GROUP BY ID
DROP TABLE #YourTable
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
我使用了这种方法,可能更容易掌握。获取一个根元素,然后连接到具有相同ID但不是“正式”名称的选项
Declare @IdxList as Table(id int, choices varchar(max),AisName varchar(255))
Insert into @IdxLIst(id,choices,AisName)
Select IdxId,''''+Max(Title)+'''',Max(Title) From [dbo].[dta_Alias]
where IdxId is not null group by IdxId
Update @IdxLIst
set choices=choices +','''+Title+''''
From @IdxLIst JOIN [dta_Alias] ON id=IdxId And Title <> AisName
where IdxId is not null
Select * from @IdxList where choices like '%,%'
使用XML路径不会完美地连接你可能期望…它会将“&”替换为“&”,也会混淆<”和“>” ...也许还有其他一些事情,不确定……但是你可以试试这个
我想到了一个变通办法…您需要替换:
FOR XML PATH('')
)
:
FOR XML PATH(''),TYPE
).value('(./text())[1]','VARCHAR(MAX)')
...或者NVARCHAR(MAX)如果这是你使用的。
为什么SQL没有一个串联聚合函数?这是PITA。
如果group by只包含一个项目,您可以通过以下方式显著提高性能:
SELECT
[ID],
CASE WHEN MAX( [Name]) = MIN( [Name]) THEN
MAX( [Name]) NameValues
ELSE
STUFF((
SELECT ', ' + [Name] + ':' + CAST([Value] AS VARCHAR(MAX))
FROM #YourTable
WHERE (ID = Results.ID)
FOR XML PATH(''),TYPE).value('(./text())[1]','VARCHAR(MAX)')
,1,2,'') AS NameValues
END
FROM #YourTable Results
GROUP BY ID