One-table queries are OK, but data is usually spread over different tables in the database. To write a query that uses data from more than one table, you need to join the tables. This article shows ways to do that.
Written by Rafael Victória-Pereira
Using one table in a Select statement won't get you very far: most databases are structured to avoid data repetition and use multiple tables to achieve that goal, which means that you'll probably have to use different tables for the actual data and its human-understandable descriptions.
Let me try to explain this with an example: