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?
Please I have no knowledge of any programming language so I need detailed explanation on the question to enable me prepare a response. It would be very much appreciated if a minimum of 3 cites can be used and referenced appropriately.
Some vendors' versions of SQL have proprietary extensions (i.e., additional functionality) not found in standard SQL. Why do you think they do this?
Some vendors' do this to make their product more sellable. They add features to the standard SQL to have better functionality and make querying a database more useful which will make their product sell better.
Another reason is that depending on the database system the standard SQL may not do what that particular vendor needs. Example: Oracle's database system might have features in it that the standard SQL may not cover so instead of waiting for the standard SQL to be updated Oracle adds its own extensions to it so it will work with their database.
A couple of references on ...
Understanding databases and how to extract information for them can be daunting. SQL makes this much easier because it is standard amongst the most common popular database systems (Oracle, MYSQL).
These questions are very commonly asked and are here to add knowledge.