-- Here's an SQL script that will find and remove snapshots without port numbers
-- when there exists a duplicate with the default port 1965.

-- Before running this DELETE though, you might want to
-- verify the matches first with this SELECT:
WITH duplicates AS (
    SELECT s1.id as id_without_port, s2.id as id_with_port, s1.url as url_without_port, s2.url as url_with_port
    FROM snapshots s1
             JOIN snapshots s2
                  ON s2.url = s1.url || ':1965'
)
SELECT * FROM duplicates;

-- Now delete them for real:
WITH duplicates AS (
    SELECT s1.id as id_without_port, s2.id as id_with_port, s1.url as url_without_port, s2.url as url_with_port
    FROM snapshots s1
             JOIN snapshots s2
                  ON s2.url = s1.url || ':1965'
)
DELETE FROM snapshots
WHERE id IN (SELECT id_without_port FROM duplicates);