提取值的爲多列

Question

我有一個表稱爲類型和數據是這樣的：

Item_Name 

Hardware \ Hardware Laptop \ Display 
Application \ Application Configuration Request 
Application \ Application File Request 
Application 

我試圖將它們分成3個不同的列。因此，試圖通過下面的查詢做：

select parsename(replace([Item_Name],'\','.'),3) as First, 
parsename(replace([Item_Name],'\','.'),2) as Second, 
parsename(replace([Item_Name],'\','.'),1) as third 
from dbo.Types 

，但我沒有得到確切的結果，我想輸出是：

First   Second          Third 
Hardware  Hardware Laptop        Display 
Application Application Configuration Request   NULL 
Application Application File Request     NULL 
Application NULL          NULL 

但我得到的輸出爲：

First   Second       Third 
Hardware  Hardware Laptop     Display 
NULL   Application      Application Configuration Request   
NULL   Application      Application File Request      
NULL   NULL       Application 

Answer 1

這可能是有用的

Declare @t table(Item_Name Varchar(100)) 
Insert Into @t 
Select 'Hardware \ Hardware Laptop \ Display' Union All 
Select 'Application \ Application Configuration Request' Union All 
Select 'Application \ Application File Request' Union All 
Select 'Application' 

;WITH CTE AS(
SELECT 
    Item_Name 
    ,NoOfOccurance = (LEN(Item_Name) - LEN(REPLACE(Item_Name, '\', ''))) 
    ,New_Item_Name = CASE (LEN(Item_Name) - LEN(REPLACE(Item_Name, '\', ''))) 
         WHEN 0 THEN 'Col1 \ Col2 \ ' +Item_Name 
         WHEN 1 THEN 'Col1 \ ' +Item_Name 
         ELSE Item_Name 
        END 
FROM @t) 
,cte2 AS(
SELECT 
    [First] = LEFT(New_Item_Name,CHARINDEX('\',New_Item_Name,0)-1) 
    , [Second] = SUBSTRING(
       New_Item_Name 
       ,CHARINDEX('\',New_Item_Name,0)+1 
       ,CHARINDEX('\',SUBSTRING(New_Item_Name,CHARINDEX('\',New_Item_Name,0)+1,len(New_Item_Name)),0)-1 
       ) 
    ,[Third] = REVERSE(LEFT(REVERSE (New_Item_Name),CHARINDEX('\',REVERSE (New_Item_Name),0)-1)) 

FROM CTE) 
SELECT 
    [First] = CASE WHEN LTRIM(RTRIM([First])) = 'Col1' THEN REPLACE([First], 'Col1', NULL) ELSE [First] END 
    ,[Second] = CASE WHEN LTRIM(RTRIM([Second])) = 'Col2' THEN REPLACE([Second], 'Col2', NULL) ELSE [Second] END 
    ,[Third]  
FROM Cte2 

//結果

First Second Third 
Hardware  Hardware Laptop  Display 
NULL  Application  Application Configuration Request 
NULL  Application  Application File Request 
NULL NULL  Application 

Answer 2

我認爲這個蠻力，但它的作品。這個想法是在最後添加足夠的斜槓來創建一個全名。這會推翻一切：

with types as (select 'Hardware \ Hardware Laptop \ Display' as item_name union all 
       select 'Application \ Application Configuration Request' union all 
       select 'Application \ Application File Request' union all 
       select 'Application' 
      ) 
select parsename(replace([Item_Name]+suffix, '\', '.'), 3) as First, 
     parsename(replace([Item_Name]+suffix, '\', '.'), 2) as Second, 
     parsename(replace([Item_Name]+suffix, '\', '.'), 1) as third 
from (select item_name, LEN(Item_name) - LEN(replace(item_name, '\', '')) as numslash, 
      REPLICATE('. ', 2-(LEN(Item_name) - LEN(replace(item_name, '\', '')))) as suffix 
     from Types 
    ) t 

一個細微的區別是，它會爲空插槽生成空格而不是NULL。如果你想要NULL，你需要額外的邏輯。

Answer 3

WITH CTE AS(
SELECT CASE LEN(Item_Name)-LEN(REPLACE(Item_Name,'\','')) WHEN 2 THEN [Item_Name] WHEN 1 THEN 
     [Item_Name]+'.' Else [Item_Name]+'..' as Item_Name 
FROM dbo.Types 
) 
SELECT parsename(Item_Name,'\','.'),3) as First, 
     parsename(Item_Name,'\','.'),2) as Second, 
     parsename(Item_Name,'\','.'),1) as third 
FROM CTE