Agree with Sean,

Recursive CTE like below,

[Code]

WITH Tree AS

(

SELECT Parent.ID[ID]

, Parent.ParentID[ParentID]

FROM Entity Parent

WHERE Parent.ID = @Parammeter

UNION ALL

SELECT Child.ID

, Child.ParentID

FROM Entity Child

INNER JOIN TreeON Child.ParentID = Tree.ID

)

SELECT *

FROM Tree

[/Code]