create table namaste_orders
(
order_id int,
city varchar(10),
sales int
)

create table namaste_returns
(
order_id int,
return_reason varchar(20),
)

insert into namaste_orders
values(1, 'Mysore' , 100),(2, 'Mysore' , 200),(3, 'Bangalore' , 250),(4, 'Bangalore' , 150)
,(5, 'Mumbai' , 300),(6, 'Mumbai' , 500),(7, 'Mumbai' , 800)
;
insert into namaste_returns values
(3,'wrong item'),(6,'bad quality'),(7,'wrong item');

--SQL to find cities where not even single order has was returned
--Achieve this without using subquery and CTE

SELECT * FROM namaste_returns;
SELECT * FROM namaste_orders;

SELECT O.city , COUNT(R.order_id)
FROM namaste_orders O LEFT JOIN namaste_returns R ON O.order_id = R.order_id
GROUP BY O.city
HAVING COUNT(R.order_id)= 0
by