Final answer:
The SQL query to select the firm name and stock price from the stock table and the exchange rate from the nation table would involve a JOIN clause to merge the two tables on a common column, such as a foreign key relating to the nation table's primary key.
Step-by-step explanation:
To select the firm name and stock price from the stock table and the exchange rate from the nation table, you need to craft an SQL query that joins these two tables on a common column. This common column should be a foreign key in the stock table that references the primary key in the nation table. Without knowing the exact schema, a hypothetical query could be:
SELECT s.firm_name, s.stock_price, n.exchange_rate
FROM stock AS s
JOIN nation AS n ON s.nation_id = n.id;
This SQL query assumes that 'nation_id' is the column in the stock table that relates to the 'id' column in the nation table, which is a common relational database design practice. Remember to replace 'firm_name', 'stock_price', 'exchange_rate', and 'id' with the actual column names used in your database.
The complete SQL query to select the firm name and stock price from the stock table and the exchange rate from the nation table is:
SELECT stock.firm_name, stock.stock_price, nation.exchange_rate FROM stock JOIN nation ON stock.country_id = nation.country_id;
This query uses the SELECT statement to specify the columns we want to retrieve (firm_name, stock_price, and exchange_rate). The FROM clause specifies the tables we want to query from (stock and nation), and the JOIN keyword is used to combine the two tables based on their common column (country_id).