DELETE FROM ITEM AS A 
  WHERE NOT EXISTS(SELECT * FROM STOCK B WHERE B.ITEM_CODE = A.ITEM_CODE);
  
DELETE FROM ITEM AS A 
  WHERE     EXISTS(SELECT * FROM STOCK B WHERE B.ITEM_CODE = A.ITEM_CODE AND B.LAST_DELIVERY_DATE < datetime('2023-06-01', '-6 months') AND B.ACTUAL_AMT = 0)
  AND A.STOCK_MANAGEMENT_TYPE = 1;