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

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