Select individual fields of a row type

Consider the address column of the employee table, which contains the fields street, city, state, and zip. In addition, the zip field contains the nested fields: z_code and z_suffix. (You might want to review the row type and table definitions of Figure 1.) A query on the zip field returns rows for the z_code and z_suffix fields. However, you can specify that a query returns only specific nested fields. The following query shows how to use dot notation to construct a SELECT statement that returns rows for the z_code field of the address column only.