I'd never run across coalesce before. I usually end up doing nested NVL calls if I'm trying to find the first non-null in a series of expressions (I'm on Oracle, btw). I've now added this function to my toolbox.
They don't seem to be in oracle. Giving more than two parameters to nvl gives me an error but works fine with coalesce. Granted they are basically the same thing if you are giving both two parameters.