I recently fielded a question about getting data out of Oracle quickly. Without much detail on the systems involved here is my answer:
I need to migrate data from Oracle to MySQL quickly (in less than 1 day). What are my options?
Oracle does not supply an out-of-the-box unload utility.
Keep in mind without comprehensive info about your environment (oracle version? server platform? how much data? what datatypes?) everything here is YMMV and you would want to give it a go on your system for performance and timing.