Book for SQL and PL/SQL

Is there any single good book where SQL and PL/SQL is covered in depth.

No, but there are lots of good SQL books, and lots of good PL/SQL books, though.

For SQL in general, you probably need a general introduction to SQL and relational databases. There are lots of these, so maybe ask on the JDBC forum for recommendations.

For SQL with a specific Oracle focus, you could look at the exam guide for the Oracle Certified Associate exams, which will give you all the info on Oracle's implementation of SQL, including any Oracle-specific functions etc.

For PL/SQL there is another Oracle exam guide, but my own favourite is Steven Feuerstein's Oracle PL/SQL Programming, which has been the definitive PL/SQL book for many years in its various editions.

There is also an excellent book called Mastering Oracle PL/SQL by Connor MacDonald which includes some excellent material on high performance PL/SQL for dealing with large volumes of data.