Where to begin with Oracle and SQL
Here is my list and everything on this list is excellent. I’m sure I missed a few good ones, but maybe people can add them in the comments.
Start with Oracle Docs, they are free and good!
Get the best books and read them
A bit old, but this is a great overview of Oracle: Practical Oracle 8i by Jonathan Lewis
After you have read the above, dive into the important details:
If you know SQL but want to get great at SQL performance, read these books
Join Online discussions and follow blogs
Oracle-L forum: www.freelists.org/list/oracle-l
OTN forums: https://forums.oracle.com/forums
Oaktable blogs: http://www.oaktable.net/oakienews
Create your own Oracle blog aggregator, here is mine: http://oracle.collected.info/
Go to conferences. First of all your local Oracle user groups and if you have the time and resources then go to the bigger conferences: