Read this SQL tutorial to learn when to use SELECT, JOIN, subselects and UNION to access multiple tables with a single statement.

How to Select a Subset in MySQL. The Structured Query Language, used in the MySQL database, has great flexibility for selecting subsets of data from database tables. SQL's SELECT statement shows ...

You often need data that are stored in separate tables. For example, you may want to produce a report that gets information about flight delays from one table and boarding capacity from another.