Efficiently Finding Supersets In MySQL Vs SPL

The MySQL database has two tables: bag table and bag item relationship table. Some bags are supersets of other bags.
bag

bag_item

Now we need to find the superset for each bag:

SQL：

SELECT
  base.id AS base_bag_id,
  s.id AS superset_bag_id
FROM bag base
JOIN bag s
   ON s.id <> base.id
  AND NOT EXiSTS (SELECT 1
    FROM bag_item bi
    WHERE bi.bag_id = base.id
      AND NOT EXISTS (SELECT 1
        FROM bag_item si
        WHERE si.item_id = bi.item_id
          AND si.bag_id = s.id
    )
);


    
    

    
    




Two layers of loop traversal are required here, and SQL requires thr...