How do I do the SQL equivalent of “DISTINCT” in CouchDB?

Question

I have a bunch of MP3 metadata in CouchDB. I want to return every album that is in the MP3 metadata, but no duplicates.

A typical document looks like this:

Answer 1

Have a look at View Cookbook for SQL Jockeys' Get Unique Values section.

Answer 2

I believe your map/reduce would look something like:

function map(doc) {
    emit(doc.album, null);
}

function reduce(key, values) {
    return null;
}

Remember to query with the extra parameter group=true