I have a collection of documents:
date: Date
users: [
{ user: 1, group: 1 }
{ user: 5, group: 2 }
]
date: Date
users: [
{ user: 1, group: 1 }
{ user: 3, group: 2 }
]
I would like to query against this collection to find all documents where every user id in my array of users is in another array, [1, 5, 7]. In this example, only the first document matches.
The best solution I've been able to find is to do:
$where: function() {
var ids = [1, 5, 7];
return this.users.every(function(u) {
return ids.indexOf(u.user) !== -1;
});
}
Unfortunately, this seems to hurt performance is stated in the $where docs:
$where evaluates JavaScript and cannot take advantage of indexes.
How can I improve this query?
The query you want is this:
db.collection.find({"users":{"$not":{"$elemMatch":{"user":{$nin:[1,5,7]}}}}})
This says find me all documents that don't have elements that are outside of the list 1,5,7.