Using recursive CTE with Ecto

Question

How would I go about using the result of a recursive CTE in a query I plan to run with Ecto? For example let\'s say I have a table, nodes, structured as so:

-- n         


        

Answer 1

I was able to accomplish this using a fragment. Here's an example of the code I used. I'll probably move this method to a stored procedure.

Repo.all(MyProj.User,
  from u in MyProj.User,
  join: un in MyProj.UserNode, on: u.id == un.user_id,
  join: nt in fragment("""
  (
    WITH RECURSIVE node_tree AS (
      SELECT *
      FROM nodes
      WHERE nodes.id = ?
    UNION ALL
      SELECT n.*
      FROM nodes n
      INNER JOIN node_tree nt ON nt.parent_id == n.id
    )
  ) SELECT * FROM node_tree
  """, ^node_id), on: un.node_id == nt.id
)