Question

请参阅下面的SQL Query，我希望在有逗号的时候拆分Document_Type列。

 DECLARE @t TABLE(Company int,Date_Of_Birth DATETIME,Department VARCHAR(50)
,Document_Type VARCHAR(50), Name VARCHAR(50), Surname VARCHAR(50)
,ID_Number VARCHAR(50), Passport_No VARCHAR(50), Job_Title VARCHAR(50)
,Start_Date DATE,End_Date DATE, Type VARCHAR(50)
)
insert @t
SELECT 302,NULL,605,'New Employee Form','Richard', 'Watts',51086,0,NULL,NULL,NULL,NULL union all
SELECT 302,NULL,605,'Personal Paticulars Form','Richard','Watts',51086,0,NULL,NULL,NULL,NULL union all
SELECT 302,NULL,605,'Advance','Richard','Watts',51086,0,NULL,NULL,NULL,NULL union all
SELECT 302,NULL,605,'Employment Agreement Signed','Richard','Watts',51086,0,NULL,NULL,NULL,NULL union all
SELECT 302,NULL,605,'Inteview Record','Richard','Watts',51086,0,NULL,NULL,NULL,NULL union all
SELECT 302,NULL,605,'leave Application','Richard','Watts',51086,0,NULL,NULL,NULL,NULL union all
SELECT 302,NULL,605,'Doctor Certificate','Richard','Watts',51086,0,NULL,NULL,NULL,NULL union all
SELECT 302,NULL,605,'Miscellaneous Documents','Richard','Watts',51086,0,NULL,NULL,NULL,NULL

--Query ','+ ('')), 1,1,
SELECT DISTINCT ID_Number, Company, Date_Of_Birth,Department ,Name ,
Surname ,Passport_No, Job_Title,Start_Date,
End_Date ,Type, STUFF((SELECT ','+ Document_Type FROM @t WHERE ID_Number = Tmp.ID_Number FOR XML PATH ('')), 1,1,'')
FROM @t Tmp

这是结果。

提前谢谢。

Answer 1

SELECT DISTINCT ID_Number, 
Company, 
Date_Of_Birth,
Department ,
Name ,
Surname ,
Passport_No, 
Job_Title,
Start_Date,
End_Date ,
Type, 
STUFF((SELECT '|'+ Document_Type 
       FROM @t 
       WHERE ID_Number = Tmp.ID_Number 
       FOR XML PATH ('')), 1,1,'')
FROM @t Tmp

Answer 2

要将文档类型作为字段而不是行，您需要使用PIVOT。这里的要点是，没有一个字段可用于获取透视字段的名称，因此我们必须创建

With N AS ( 
  SELECT *
       , Pvt_Col = 'Document_Type_' 
       + CAST(Row_Number() OVER (PARTITION BY ID_Number 
                                 ORDER BY Document_Type) as VARCHAR) 
  FROM @t )

如果知道不同的值并且很少可以使用CASE

伪造它

With N AS ( 
  SELECT *
       , Pvt_Col = 'Document_Type_' 
       + CAST(Row_Number() OVER (PARTITION BY ID_Number 
                                 ORDER BY Document_Type) as VARCHAR) 
  FROM @t ) 
SELECT Company, Date_Of_Birth, Department, Document_Type, Name
     , Surname, ID_Number, Passport_No, Job_Title, Start_Date
     , End_Date, Type
     , Document_Type_1 = MAX(CASE WHEN Pvt_Col = 'Document_Type_1' 
                                  THEN Document_Type
                                  ELSE NULL
                             END)
     , Document_Type_2 = MAX(CASE WHEN Pvt_Col = 'Document_Type_2' 
                                  THEN Document_Type
                                  ELSE NULL
                             END)
...
FROM   N
GROUP BY Company, Date_Of_Birth, Department, Document_Type, Name
       , Surname, ID_Number, Passport_No, Job_Title, Start_Date
       , End_Date, Type

如果不同的值更多未知，我们必须使用metascripting，例如创建一个脚本来创建要执行的脚本，这种特殊类型的元脚本称为动态轴

Declare @q varchar(MAX)

With N AS (
  Select *
       , Pvt_Col = 'Document_Type_' 
       + Cast(Row_Number() OVER (PARTITION BY ID_Number ORDER BY Document_Type) as varchar)
  From   @t
), C (Cols) As (
  Select STUFF((SELECT distinct ',' + QUOTENAME(Pvt_Col) 
                FROM   N
                FOR XML PATH(''), TYPE
               ).value('.', 'NVARCHAR(MAX)') 
              , 1, 1, '')
)
Select @q 
       = 'With N AS (
          SELECT *, Pvt_Col = ''Document_Type_'' 
               + Cast(Row_Number() OVER (PARTITION BY ID_Number ORDER BY Document_Type) as varchar)
          FROM   @t
        )           
        SELECT ID_Number, Company, Date_Of_Birth, Department, Name
             , Surname, Passport_No, Job_Title, Start_Date
             , End_Date, Type
             , ' + Cols + ' 
        FROM  (SELECT Company, Date_Of_Birth, Department, Document_Type, Name
                    , Surname, ID_Number, Passport_No, Job_Title, Start_Date
                    , End_Date, Type, Pvt_Col
               FROM N
           ) x
           PIVOT 
           (max(Document_Type) for Pvt_Col in (' + Cols + ')) pvt'
From C

execute(@q)

调整我的SQL查询以允许不同列中的文档类型

2 个答案: