Fourth in a series of posts in response to Tim Ford's #EntryLevel Challenge.
SQL supports three types of join operation. Most developers learn the inner join first. But there are two other join operations you should know about. These are the outer join, and the full outer join. These additional join types allow you to write in essence could be termed as optional joins.
The so-called inner-join is the default. It's the happy path from a theory perspective, and it's the join type most SQL developers learn first. Use it to combine related rows from two or more tables.
For example, perhaps you want to report on all the customers in the AdventureWorks database. You might begin working that business problem by writing the following query: