Question

I have a table called tblmodules which has 3 columns: moduleid,name,parent_id. The column parent_id takes values of other modules. ex:

Moduleid      Name       Parentid
--------     -----       --------
1           grandparent    Null
2            parent         1
3           child           2

I want a stored procedure that takes the parent’s Id and Name of a child giving a level. So i develop the following.

        @moduleid bigint,
    @level int

AS
BEGIN
    -- SET NOCOUNT ON added to prevent extra result sets from
    -- interfering with SELECT statements.
    SET NOCOUNT ON;

    declare @parentid bigint
    declare @name nvarchar(100)
    set @parentid = (select parentid from tblModules where ModuleId = @moduleid)


    declare @counter int
    set @counter = 1

    while @counter < @level
    begin

        set @parentid = (select parentid from tblModules where ModuleId = @parentid)
        set @name = (select Name from tblModules where ModuleId = @parentid)

        set @counter = @counter + 1
    end

    select @parentid AS ID
    select @name as Name

end

The procedure works fine and gets the correct Id of the parent, but the name remains the same as the child. For ex i am executing it giving the values @moduleid: 3 and @level:2.
I am getting result ID: 1 which is correct but Name: child instead of Grandparent. Any help?

Answer 1

In my script I use CTE for level finding Modules that will join with their ParentLevel(@level)

CREATE PROCEDURE dbo.ParentLevelName
 (
  @moduleid bigint,
  @level int
  )
AS
BEGIN
  SET NOCOUNT ON;

  ;WITH ParentTree(Parentid, Moduleid, Name, ParentLevel)
  AS
   (
    SELECT Parentid, Moduleid, Name, 0 AS ParentLevel
    FROM tblmodules
    WHERE Parentid IS NULL
    UNION ALL
    SELECT t.Parentid, t.Moduleid, t.Name, p.ParentLevel + 1
    FROM tblmodules t JOIN ParentTree p ON t.Parentid = p.Moduleid 
    )
  SELECT p.Parentid, p.Moduleid, p.Name, p2.Name PerantLevelName
  FROM ParentTree p LEFT JOIN ParentTree p2 ON p.ParentLevel - @level = p2.ParentLevel
  WHERE p.Moduleid = @moduleid
END

Demo on SQL Fiddle