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 SQL syntax that creates
the ROW types and table..) 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. Figure 1: Query