expression [ NOT ] IN 
{ ( subquery ) |  ( value-expr, ... ) }

value-expr are expressions that take on a single value, which may be a string, a number, a date, or any other SQL data type.

An IN condition, without the NOT keyword, evaluates according to the following rules:

You can reverse the logic of the IN condition by using the NOT IN form.

The following search condition expression IN ( values ) is identical to the search condition expression = ANY ( values ). The search condition expression NOT IN ( values ) is identical to the search condition expression <> ALL ( values ).

Select the company name and state for customers who live in the following Canadian provinces: Ontario, Manitoba, and Quebec.

SELECT CompanyName , Province
FROM Customers
WHERE State IN( 'ON', 'MB', 'PQ')