SQL is a standardized query language for requesting information from a database. You can verify your knowledge by trying to answer a few simple questions.
Chemistry is the science that studies the composition, structure and properties of matter and the changes that occur during chemical reactions. Answer a few questions to see how good you really are in Chemistry?
If you know how to sing or hum a song, but don't know the title or the artist performing it, you can use a midomi website which will help you find the the song.