SELECT Customer_Name FROM Clients EXCEPT SELECT T2.Customer_Name FROM Bookings AS T1 JOIN Clients AS T2 ON T1.Customer_ID  =  T2.Client_ID
What are the names of the clients who do not have any booking?
SELECT Customer_Name FROM Clients EXCEPT SELECT T2.Customer_Name FROM Bookings AS T1 JOIN Clients AS T2 ON T1.Customer_ID = T2.Client_ID
select customer_name from clients except select t2 . customer_name from bookings as t1 join clients as t2 on t1 . customer_id = t2 . client_id
What are the names of the clients who do not have any booking ?