DELETE FROM ITEM
 WHERE ITEM_CODE IN (SELECT ITEM_CODE 
                       FROM ITEM IT
                      WHERE NOT EXISTS (SELECT ITEM_CODE
                                          FROM STOCK ST
                                         WHERE IT.ITEM_CODE = ST.ITEM_CODE
                                        )
                     UNION 
                     SELECT ST.ITEM_CODE
  FROM STOCK ST INNER JOIN ITEM IT
                   ON ST.ITEM_CODE =  IT.ITEM_CODE
 WHERE IFNULL(LAST_DELIVERY_DATE,'2023-06-01') <= DATE('2023-06-01', '-6 months')
   AND IT.STOCK_MANAGEMENT_TYPE = 1
  GROUP BY ST.ITEM_CODE
                        HAVING SUM(ACTUAL_AMT) = 0
                    )
   AND STOCK_MANAGEMENT_TYPE = 1
;