Properties of collection data types

You can create a collection with elements of any data type listed in your project except SERIAL, SERIAL8, and BIGSERIAL. You can define a collection type of an existing collection or row data type. For example, you can define a list of a set of integers in SQL:

LIST(SET(integer not null))

You can also create collections of opaque or distinct data types.

The type constructor determines the structure of the collection. The following table shows the options between the type constructors.

Constructor	Elements Ordered?	Duplicates Allowed?
LIST	Yes	Yes
MULTISET	No	Yes
SET	No	No