Just weighing in here with a nice solution I have been using. This is similar to Lucky Soni's solution above in that it supports aggregation, but doesn't require hard coding of the field names.
cursor = db.<collection_name>.<my_query_with_aggregation>;
headerPrinted = false;
while (cursor.hasNext()) {
item = cursor.next();
if (!headerPrinted) {
print(Object.keys(item).join(','));
headerPrinted = true;
}
line = Object
.keys(item)
.map(function(prop) {
return '"' + item[prop] + '"';
})
.join(',');
print(line);
}
Save this as a .js file, in this case we'll call it example.js and run it with the mongo command line like so:
mongo <database_name> example.js --quiet > example.csv