delete from item
where stock_management_type = 1 
and item_code not in ( select item_code from stock where stock.item_code = item.item_code )
or item_code in ( 
    select item_code from stock 
        where stock.item_code = item.item_code
        group by item_code    
        having max(ifnull(last_delivery_date, '2999-01-01')) <= date('2023-06-01','-6 months')
        and actual_amt = 0
)