Some vendors' versions of SQL have proprietary extensions (i.e., additional functionality) not found in standard SQL.
Why do you think they do this? In your view, what are the advantages and disadvantages of doing this?
Is it a good idea for end users (developers, DBAs, etc.) to use these extensions? Discuss how SQL differs from a programming language that you are familiar with.
What are your general opinions of SQL so far? Is it easy or hard? Useful or not useful?