WITH deldata AS (
SELECT ITEM_CODE
FROM STOCK 
GROUP BY ITEM_CODE 
HAVING
    MAX(IFNULL(LAST_DELIVERY_DATE, '2999-12-31')) <= DATE ('2023-06-01', '-6 months') 
    AND SUM(ACTUAL_AMT) = 0
)
DELETE
FROM ITEM AS t0
WHERE STOCK_MANAGEMENT_TYPE = 1
	AND ( NOT EXISTS(
		SELECT 1
		FROM STOCK AS t1
		WHERE t0.ITEM_CODE = t1.ITEM_CODE
		)
	OR EXISTS(
		SELECT 1
		FROM deldata AS t2
		WHERE t0.ITEM_CODE = t2.ITEM_CODE
		)
	)