Using examples as well as descriptions, and references to Books Online, show the documentation available for datatypes, explain the available data types and show how data can be passed into and out of variables.
After looking into a question at EE, a thought came to my mind that I considered would make a good article. "Transform Text copied from Excel Table into Real Table in SQL" as it is totally possible to do. Here's the result.
This article discusses various scenarios that can end up in a DBCC CHECKDB process getting stuck in a Killed/Rollback state and how to resolve the problem.