Getting sum of MySQL-fields?

I have a table in a MySQL database where one field contains only numbers.
Now I want to pull the sum of those numbers out from the database via PHP. How does one do that?? I’ve tried many different things, but I can’t get it to work.

Let’s say this is the table:


+--------+
| number |
+--------+
|  1     |
|  2     |
|  3     |
+--------+

How can I get the result from the database to be 6 (1+2+3) ?

Thanks
Johan aka kalliban