sql查父節點小筆記

//因爲是取根節點下第一層所對0做了一個判斷 這裏自已能夠根據自已要的數據來取
ALTER function [dbo].[f_pid](@id varchar(60)) returns @t_level table(pid varchar(60),sortNum int)
as
BEGIN
  DECLARE @sortNum int 
  SET @sortNum = 0
  
  --獲得當前id的父id, 
  select @id = ParentId, @sortNum =Sortnum 
  from Sys_Departments where keyId = @id and ParentId is not NULL
  
  while @@ROWCOUNT > 0
  BEGIN  --循環輸入插入
     insert into @t_level select @id, @sortNum
     --------------------------------------------
     --繼續找父id
     select @id = ParentId, @sortNum = Sortnum from Sys_Departments
     where keyId = @id and ParentId is not NULL 
     --------------------------------------- 
     
     IF @id<>'0'
        BEGIN
            DELETE @t_level --刪除
        END
     ELSE
        BEGIN
            --只取當前根節點的下一個最高父節點
            BREAK
        END
         
  end
  return
end