Read this SQL tutorial to learn when to use SELECT, JOIN, subselects and UNION to access multiple tables with a single statement. It’s sometimes difficult to know which SQL syntax to use when ...

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.

If you are working with Excel spreadsheets or workbooks, juggling multiple tables of data, at some time you might need to combine them into one. Rather than spending hours manually copying and pasting ...