SQL Query for Parent Child Relationship

Question

I have db table with parent child relationship as:

NodeId    NodeName    ParentId
------------------------------
1         Node1       0
2         Node2              


        

Answer 1

And just to make sure it works if its a parent of itself (otherwise it will recurse until it breaks):

   with [CTE] as (
        select * from [TheTable] c where c.[ParentId] = 1
        union all
        select * from [CTE] p, [TheTable] c where c.[ParentId] = p.[NodeId]
        and c.[ParentId] <> c.[NodeId]
    )
    select * from [CTE]