delete from ITEM
where STOCK_MANAGEMENT_TYPE = 1 and ITEM_CODE not in (
  select ITEM_CODE
  from STOCK
  where LAST_DELIVERY_DATE = (
    select max(LAST_DELIVERY_DATE) from STOCK AS S
    where S.ITEM_CODE = STOCK.ITEM_CODE
    having max(LAST_DELIVERY_DATE) < DATE('2023-06-01', '-6 month')
  ) and ACTUAL_AMT = 0
)