SQL Server 2017

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DROP TABLE IF EXISTS Edges
CREATE TABLE Edges(from_node int, to_node int);
INSERT INTO Edges VALUES (1,2),(1,3),(1,4),(5,1);
4 rows affected

select * from edges


from_node
to_node


1
2

1
3

1
4

5
1


with cte as (
      select 1 as from_node, e.from_node as to_node, 1 as lev
      from edges e
      where not exists (select 1 from edges e2 where e2.to_node = e.from_node)
      union all
      select e.from_node, e.to_node, lev + 1
      from cte join
           edges e
           on e.from_node = cte.to_node
      -- where lev < 5
     )
select *
from cte
order by lev desc


from_node
to_node
lev


1
2
3

1
3
3

1
4
3

5
1
2

1
5
1