How does an OUTER JOIN differ from an INNER JOIN?

An OUTER JOIN is designed to return all records from one table and the matching records from another table. When there is no match, it still includes the records from the first table, filling in any columns from the second table with NULL values. This characteristic of including non-matching rows is what distinguishes it from an INNER JOIN, which only returns rows where there is a match in both tables.

This feature is particularly useful when you want to retain all data from one dataset while filling in gaps with data from another, which is invaluable in various data analysis scenarios. For instance, if you are working with customer information and order data, using an OUTER JOIN allows you to list all customers, even those who haven't placed any orders, while INNER JOIN would exclude customers without corresponding orders, losing potentially important information.

The other choices do not accurately represent the functionality of OUTER JOIN. For example, OUTER JOIN does return data and is not confined to a single table, nor is it inherently slower than INNER JOIN, as performance may vary depending on the data complexity and indexing rather than join type alone.