Final answer:
The SQL query returns the stock firms and their respective total stock value in Australian dollars from the stock and nation tables, filtered specifically for records with the nation code 'AUS'.
Step-by-step explanation:
The SQL query in question is designed to retrieve a dataset from two tables named stock and nation. These tables are joined on the condition that the natcode column in the stock table matches the natcode column in the nation table. The query selects two columns: The stkfirm column from the stock table.
A calculated column that multiplies stkprice, quantity from the stock table by exchrate from the nation table, providing a value in Australian dollars since the natcode is specified as 'AUS' in the WHERE clause. The result will be a list of stock firms represented by stkfirm and the calculated total value of their stock in Australian currency for those entries that have the natcode 'AUS'.