The following queries produce the same results.
Select DISTINCT customer_name, customer_city
from customer, salesman
where customer.salesman_id = salesman.salesman_id
and salesman.lname = 'SMITH';
select customer_name, customer_city
from customer
where customer.salesman_id =
(select salesman_id
from salesman
where lname = 'SMITH');

Question

Quizplus · Accepted Answer

Both queries retrieve the customer name and city for customers assigned to the salesman with the last name "Smith". The first query uses an inner join to match the salesman ID between the customer and salesman tables, while the second query uses a subquery to retrieve the salesman ID for "Smith" and then filters the customer table based on that ID. The use of DISTINCT in the first query ensures that only unique customer names and cities are returned.

The Following Queries Produce the Same Results