使用 FOR XML 路径的 sql server 中的字符串连接问题。

Question

我有以下数据

UniqueID    ID  data
1       1   a
2       1   2
3       1   b
4       1   1
5       2   d
6       2   3
7       2   r

预期的输出是

ID  ConcatData
1   a,-,-,b,-
2   d,-,-,-,r

我们要做的是，数字字符的数量必须用那些破折号（'-'）替换，然后我们需要合并相应 id 的数据。

到目前为止，我正在使用以下查询

declare @t table(UniqueID int identity(1,1), ID int, data varchar(10))  
insert into @t select 1, 'a' union all  select 1, '2' union all select 1, 'b' 
union all select 1, '1' union all select 2, 'd' union all select 2, '3' 
union all select 2, 'r' 

select * from @t

;with cte1 as 
(     
    select 
        UniqueId
        , id
        , data
        , case when isnumeric(data) = 1 then cast(data as int) end Level
         from @t     
    union all     
    select 
        UniqueId
        , id
        , CAST('-' as varchar(10))
        , Level - 1     
    from cte1     
    where Level > 0 ) 
,cte2 as
(
select id, GroupID = Dense_Rank() Over(Order by id),data, DataOrder = ROW_NUMBER() over(order by UniqueID, Level)
from cte1 
where Level is null or data = '-' 
) 

SELECT
ID
, (select data + ',' 
from cte2 t2 
where t2.GroupID = t1.GroupID
for XML path('')
) as ConcatData
from cte2 t1
group by t1.ID ,t1.GroupID

但是输出是

ID  ConcatData
1   a,b,-,-,-,
2   d,r,-,-,-,

也就是说，我无法在字符之间放置破折号（'-'）。

请帮忙

Answer 1

试试这个：

;with cte1 as
(
select 
UniqueId
, id
, data
,case when isnumeric(data) = 1 
    THEN replicate(',-',data) 
    ELSE ',' + data end as string
from @t
)

select 
id
,LTRIM(STUFF(
    (
    SELECT
      ' ' + t2.String
    FROM Cte1 t2
    WHERE t2.id = t1.id
    FOR XML PATH('')
    ), 2, 1, ''
  )) As concatenated_string
from cte1 t1 group by t1.ID ,t1.ID 

适用于上面的示例数据，可能比使用游标快一点

Answer 2

下面是创建表

Create table #temp
(
    IDUnique int Identity(1,1),
    ID int, 
    data varchar(100)
)

以下是您建议的记录。

Insert into #temp(ID, data) Values(1, 'a')
Insert into #temp(ID, data) Values(1, '2')
Insert into #temp(ID, data) Values(1, 'b')
Insert into #temp(ID, data) Values(1, '1')
Insert into #temp(ID, data) Values(2, 'd')
Insert into #temp(ID, data) Values(2, '3')
Insert into #temp(ID, data) Values(2, 'r')

以下是游标实现

declare @IDUnique int
declare @ID int
declare  @data varchar(100)
declare @Latest int
declare @Previous int
declare @Row int

set @Latest = 1
set @Previous = 1

Create Table #temp1
(
    ID int,
    data varchar(100)
)

--SELECT Row_Number() Over(Order by IDUnique) Row, IDUnique, ID, data  From #temp


DECLARE @getAccountID CURSOR SET @getAccountID = CURSOR FOR SELECT Row_Number() Over(Order by IDUnique) Row, IDUnique, ID, data  From #temp
OPEN @getAccountID
FETCH NEXT FROM @getAccountID INTO @Row, @IDUnique, @ID, @data
WHILE @@FETCH_STATUS = 0
BEGIN
    IF(@Row = 1)
    Begin
        Set @Previous = @ID
        Set @Latest = @ID
        Insert into #temp1(ID, data)values(@Previous, @data)
    End
    Else If (@Previous <> @ID)
    Begin
        Set @Previous = @ID
        Set @Latest = @ID
        Insert into #temp1(ID, data)values(@Previous, @data)
    End
    Else
    Begin
        Declare @number int
        if(ISNUMERIC(@data) = 1)
        Begin
            Set @number = Convert(int , @data)
            While(@number <> 0)
            Begin
                Update #temp1 Set Data  = Data + ',-' Where ID = @ID
                Set @number = @number - 1
            End
        End
        Else    
        begin
            Update #temp1 Set Data  = Data + ',' + @data Where ID = @ID
        End
    End

    FETCH NEXT FROM @getAccountID INTO @Row, @IDUnique, @ID, @data
END
CLOSE @getAccountID
DEALLOCATE @getAccountID

Select * from #temp1
Select * from #temp
Drop Table #temp

这是最终结果集