It often makes things easier if we all refer to the various features and techniques within MC in a uniform way...
So to that end, the page linked above by bspachman describes what are referred to within MC as "advanced expressions". The page lists the available functions and some usage examples.
Calculated fields are a little different. You can use "advanced expressions" and/or any other combination of existing library fields to create "Calculated Fields".
To create a calculated field, go to: "Tools > Options > Library and Folders > User Library Fields > Add Field" and you will be presented with the following dialogue:
You name your field, then select the "Calculated Data" option and enter your field template in the box provided. You can put just about anything you can imagine in there, someting simple such as [track #]-[artist]-[name] would create a field like so using existing database information.
Many neat things can be achieved by using calculated fields, Here are two examples of using calculated fields for two very different applications, and perhaps interesting, in both cases you never really use the fields to display their data directly within MC, though you could do if you really wanted to, as once created, calculated fields can be listed, searched or whatever, just like any normal field.
1. In
this example, I've taken the [date (filename friendly)] field and used it to create two new calculated fields which are then used to sort my images "Newest First", but "Oldest First" within each day so that the photos are shown in the order in which they were actually taken.
2. And in
this example, I've set up a couple of calculated fields to use in a web photo gallery. The fields are only ever used by the gallery template, and when called, all the relevant html code plus required database info is inserted into the web page.
Neat? I like to think so. Unique? I think so too. Well worth the entry fee if you ask me
-marko.