y in (x, ..., z)

y = x or ... or y = z

(x, ..., z) represents a list of expressions, each of which evaluates to a single value. None of the expressions (y, x, or z) can be subqueries. The in predicate returns true if y is equal to one of the values in the list represented by (x, ..., z).

y not in (x, ..., z)

not (y in (x, ..., z))

(x, ..., z) represents a list of expressions, each of which evaluates to a single value. The not in predicate returns true if y is not equal to any value in the list represented by (x, ..., z). None of the expressions (y, x, or z) can be subqueries.

y in (subquery)

The subquery must be specified in parentheses and can refer to only one column in its select clause. The predicate returns true if y is equal to one of the values returned by the subquery.

y not in (subquery)

The subquery must be specified in parentheses and can refer to only one column in its select clause. The predicate returns true if y is not equal to any of the values returned by the subquery.