DELETE FROM ITEM
WHERE (
  ITEM_CODE NOT IN (SELECT DISTINCT ITEM_CODE FROM STOCK)
  OR ITEM_CODE IN (
    SELECT ITEM_CODE FROM STOCK
    GROUP BY ITEM_CODE
    HAVING MAX(LAST_DELIVERY_DATE) <= DATE('2023-06-01', '-6 months')
      AND SUM(ACTUAL_AMT) = 0
  )
) AND STOCK_MANAGEMENT_TYPE = 1