referer recursive 2

DROP FUNCTION IF EXISTS get_referers(param_user_id bigint, param_user_bm_id SMALLINT) cascade;
CREATE FUNCTION get_referers(param_user_id bigint, param_user_bm_id SMALLINT)
returns TABLE  (
        referer_id bigint,
        referer_level INTEGER
)
AS $end$
    BEGIN
        RETURN query WITH recursive tree AS (
            SELECT
                users.referer_id AS referer_id,
                (
                    SELECT COUNT(*) % 5 + 1
                    FROM user_bms
                    WHERE
                        user_bms.user_id=users.referer_id
                    AND
                        user_bms.bm_id=param_user_bm_id
                )::INTEGER AS referer_level
            FROM users
            WHERE users.user_id = param_user_id

            UNION

            SELECT
                users.referer_id AS referer_id,
                tree.referer_level::INTEGER - CASE WHEN user_bms IS NULL THEN 0 ELSE 1 END AS referer_level
            FROM users
            left join user_bms
                ON user_bms.user_id = users.user_id AND user_bms.bm_id = param_user_bm_id
            join tree
                ON tree.referer_id = users.user_id  AND users.user_id != users.referer_id
            WHERE
                tree.referer_level - CASE WHEN user_bms IS NULL THEN 0 ELSE 1 END > 0
            )
            SELECT * FROM tree ORDER BY referer_level limit 1;
    END;
$end$
language plpgsql;


SELECT * FROM get_referers(1122::bigint, 1::SMALLINT);