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