Question

I’ve the following entity persisted on mongo in a users collection:

{
    "fullname": "Luke Tomson",
    "nicknames": [
        {
            "name": "lukeone",
            "created": ISODate("2011-05-18T19:42:56.411Z")
        },
        {
            "name": "magicluke",
            "created": ISODate("2012-01-12T19: 42: 56.411Z")
        },
        {
            "name": "superluke",
            "created": ISODate("2012-03-27T19: 42: 56.411Z")
        }
    }
]
}

How do I get the last nickname name for a user whose fullname is "Luke Tomson" ? And more specifically, how do I retrieve in the mongo shell a specific index (the first or the last) of a sorted array that was sorted upon a specific field (in this case, created).

Thanks

Answer 1

From the documentation, the second object passed to a .find is a selection of what portions of the object you want returned.

So, what you want is basically:

db.users.find({"fullname": "Luke Tomson"}, {"nicknames": { $slice: -1 } });

Though you might also want to return the _id if there are multiple “Luke Tomson”s in your DB and you need to uniquely identify them.