This is a very important feature for reports. And we have implement it using the same internal engine as the Valentina SQL format() function.
You can read Valentina WIKI: http://valentina-db.com/dokuwiki/doku.php?id=valentina:vcomponents:vsql:reference:expr:funcs_string#format
For any output field you can specify in the inspector its pattern and kind of pattern (number, currency, …).