-- Inspect duplicates first
WITH duplicate_participants AS (
    SELECT
        shipcall_id,
        participant_type,
        COUNT(*) AS cnt
    FROM times
    GROUP BY shipcall_id, participant_type
    HAVING COUNT(*) > 1
)
SELECT
    t.*
FROM times AS t
JOIN duplicate_participants AS d
    ON d.shipcall_id = t.shipcall_id
   AND (d.participant_type <=> t.participant_type)
ORDER BY t.shipcall_id, t.participant_type, t.id;

-- Delete all but the highest-id entry per (shipcall_id, participant_type)
WITH ordered_times AS (
    SELECT
        id,
        ROW_NUMBER() OVER (
            PARTITION BY shipcall_id, participant_type
            ORDER BY id DESC
        ) AS rn
    FROM times
)
DELETE FROM times
WHERE id IN (
    SELECT id
    FROM ordered_times
    WHERE rn > 1
);

-- Optional: re-check that no duplicates remain
WITH duplicate_participants AS (
    SELECT
        shipcall_id,
        participant_type,
        COUNT(*) AS cnt
    FROM times
    GROUP BY shipcall_id, participant_type
    HAVING COUNT(*) > 1
)
SELECT COUNT(*) AS remaining_duplicates FROM duplicate_participants;