select c.CUST_CODE as CODE, c.CUST_NAME as NAME, count(*) as CNT from
(select distinct CUST_CODE, ORDER_DATE from ORDERS 
where substr(ORDER_DATE,1,7) = '2023-07'
group by CUST_CODE, ORDER_DATE) as o
left outer join CUSTOMER as c on o.CUST_CODE = c.CUST_CODE
group by CODE
order by CNT desc, CODE desc;

-- select distinct CUST_CODE, ORDER_DATE from ORDERS 
-- group by CUST_CODE, ORDER_DATE