recursive sql

r.sql

    WITH RECURSIVE cte (id, body, op_id, path, comment_id, depth)  AS (
    SELECT id,
        body,
        op_id,
        array[id] AS path,
        comment_id,
        1 AS depth
    FROM comments
    WHERE comment_id = 0 AND post_id = $1
    UNION ALL
    SELECT comments.id,
        comments.body,
        comments.op_id,
        cte.path || comments.id,
        comments.comment_id,
        cte.depth + 1 AS depth
    FROM comments
    JOIN cte ON comments.comment_id = cte.id
    )
    SELECT id, body, op_id, comment_id, path, depth FROM cte
    ORDER BY path;