Final answer:
Use a subquery in SQL to find the course with the lowest cost by selecting the minimum cost and then fetching the corresponding course details such as course number and description.
Step-by-step explanation:
To show which course has the lowest cost, including the course number, description, and cost, you can use a subquery in SQL. This subquery will select the minimum cost from the table where course data is stored, and then the main query will fetch the corresponding course details that match this minimum cost.
An example of this would be:
SELECT course no, description, cost.
FROM courses
WHERE cost = (SELECT MIN (cost) FROM courses).
In this query, the WHERE clause uses a subquery that finds the minimum cost in the course table. The main query then matches this minimum cost to the corresponding course details and displays the course number, description, and the minimum cost.