How to insert a footer of a single row?

Hot to put a footer with a single row?

Example:

-------------------------------
|column1 | columns1 | column3 |
|-------------------------------
| 1 | 2 | 3 |
|------------------------------
|Footer with a single row |
-------------------------------

Thanks!

If you search the forum you will find an example of doing this on the header and I bet that doing it to the footer is done the same way.