If you are new to Oracle, dont waste your time with interview questions. A good interviewer will be able to tell right away that you've never used the product. You can study the answers to questions until you are blue in the face, but you'll never understand how it actually works. If you are receiving a technical interview, your interviewer will probably be a developer with 20 years experience. You can bet he is making the questions up off the top of his head - so any variation, and you won't know the answer.
I applaud your effort to learn Oracle...just dont try to take shortcuts. I can tell you it will not work and will only hurt you in the end. As others have echoed, take your time and practice practice. It can be frustrating in the beginning, but will benefit you in the end. If you want more links, look at the sticky on the top of the page that Tony nicely provided for everyone.