Невозможно выполнить динамический поворот в SQL Server 2008 R2

Question

Мне нужно сделать поворот в SQL Server 2008 R2. У меня есть таблица EMP с записями сотрудников, а затем одна таблица Child, в которой хранятся связанные дочерние записи.

Теперь я хочу создать одну запись для каждого сотрудника на выходе. Я не уверен, как разместить Child1Name, Child2Name, Child3Name .... Child99Name на стороне столбца. Ниже приведен пример ввода и вывода. ТИА.

Answer 1

/* 
    My Sql server 2012 
    the code below can run at above 2005 
    */ 
    set nocount on 
    ;with EmpTable as (
         select * 
         from (values(1,'John'),(2,'Tim'),(3,'Steve')) as a(ID,Name) 
        ), 
      ChildTable as(
         select * 
         from (values(1,1,'Tina'),(2,1,'Mike'),(3,2,'Mona'),(4,3,'Zane'),(5,3,'Diana'),(6,3,'Marry')) as b(ID,EmpID,Name) 
         ), 
      sourceData as(
         select a.Name,b.EmpID,b.Name as ChildName,row_number() over(partition by EmpID order by B.ID,b.Name) as rn 
         from EmpTable as a inner join ChildTable as b on a.ID = b.EmpID 

         ) 
      select EmpID,Name,[1] as Child1Name,[2] as Child2Name,[3] as Child3Name 
      from sourceData as a pivot (max(ChildName) for rn in([1],[2],[3]))as b 
    /* 
    EmpID  Name Child1Name Child2Name Child3Name 
    ----------- ----- ---------- ---------- ---------- 
    1   John Tina  Mike  NULL 
    2   Tim Mona  NULL  NULL 
    3   Steve Zane  Diana  Marry 
    */ 



/* 
Dynamic pivoting 
My Sql server 2012 
the code below can run at above 2005 
*/ 
--step 1 : 
set nocount on 
;with EmpTable as (
        select * 
        from (values(1,'John'),(2,'Tim'),(3,'Steve')) as a(ID,Name) 
       ), 
     ChildTable as(
        select * 
        from (values(1,1,'Tina'),(2,1,'Mike'),(3,2,'Mona'),(4,3,'Zane'),(5,3,'Diana'),(6,3,'Marry')) as b(ID,EmpID,Name) 
        ), 
     sourceData as(
        select a.Name,b.EmpID,b.Name as ChildName,row_number() over(partition by EmpID order by B.ID,b.Name) as rn 
        from EmpTable as a inner join ChildTable as b on a.ID = b.EmpID 

        ) 
     select * into #a 
     from sourceData 

--Step 2: 
     declare @PivotColumn as varchar(5000),@DisplayColumn as varchar(5000),@Sql as nvarchar(4000) 
    ;with columnData as (select distinct rn from #a) 
     select @PivotColumn = isnull(@PivotColumn,'')+quotename(cast(rn as varchar))+',',@DisplayColumn= isnull(@DisplayColumn,'')+quotename(cast(rn as varchar))+' as Child'+cast(rn as varchar)+'Name,' 
     from columnData 
     set @PivotColumn = left(@PivotColumn,len(@PivotColumn)-1) 
     set @DisplayColumn = left(@DisplayColumn,len(@DisplayColumn)-1) 
    set @Sql = 'select EmpID,Name,'+@DisplayColumn+' from #a as a pivot(max(ChildName) for rn in ('+@PivotColumn+')) as b' 

    exec sp_executesql @sql 
/* 
EmpID  Name Child1Name Child2Name Child3Name 
----------- ----- ---------- ---------- ---------- 
1   John Tina  Mike  NULL 
2   Tim Mona  NULL  NULL 
3   Steve Zane  Diana  Marry 
*/