tranquil-pds/migrations/20260122_backup_storage_key_unique.sql

DELETE FROM account_backups a
WHERE EXISTS (
    SELECT 1 FROM account_backups b
    WHERE a.storage_key = b.storage_key
    AND a.created_at < b.created_at
);

CREATE UNIQUE INDEX idx_account_backups_storage_key ON account_backups(storage_key);