If you wanted to search a bunch of values, you would write a WHERE clause with the values joined by the OR operator. A more readable WHERE clause would be to use the IN or to exclude values the NOT IN operator.
SELECT CompanyName, City
FROM Customers
WHERE City IN ('Berlin', 'Madrid')
NOT IN operator can be used to exclude a list of values:
SELECT CompanyName, City
FROM Customers
WHERE City NOT IN ('Berlin', 'Madrid')
