Using arrays to process element collections

While the PostgreSQL data types that you have explored so far allow you to store many different types of data, occasionally you will want to store a series of values in a single cell. For example, you might want to store a list of the products that a customer has purchased, or the employee ID numbers associated with a specific dealership. For this scenario, PostgreSQL offers the ARRAY data type, which allows you to store a list of values.

PostgreSQL arrays allow you to store multiple values of the same type in a field in a table. For example, consider the following first record in the customers table:

 customer_id | title | first_name | last_name | suffix |       email       | gender |  ip_address   | phone | street_address | city | state | postal_code | latitude | longitude |     date_added
-------------+-----...