In Following example you can see how to fetch data from "post" table and how to insert into "post_copy" table, so basically you have to select field of one that you want to copy and second one give name of table with proper field that you want insert. But don't forgot to give a name of field otherwise it generate error.
If you are working on php or any php framwork and you want to copy one table into other table by using sql query, so you could do it using simple SELECT and INSERT statement. just you need to think how you can use.
INSERT INTO `post_copy` (name,slug,status)
SELECT name,slug,'1' FROM `post`
I hope it could help you...