Upgrade JCC extension from J2.5 -> J3.x

Wow, this article is great!   Upgrade your Joomla 2.5 Component to Joomla 3 Using the SQL Import 

1) transfer the db tables of your extension from the J2.5 site to the J3.x site.
Use phpmyadmin or any other db tool.

2) Follow the instructions in the above article, using sql import.

3) Install your new J3.x extension. A great feature is that all new/extra fields are also added to your current tables (filled with your data). For example created_by or any other missing field is seamlessly added!

Thanks for the import function!