mongoDB distinct & where in same query?

Question

Let\'s say I have the following documents

Article { Comment: embedMany }

Comment { Reply: embedMany }

Reply { email: string, ip: string }

Answer 1

Maybe you could try this

db.Article.aggregate([
{$unwind: "$Comment"},
{$unwind: "$Comment.Reply"},
{$match: {"Comment.Reply.email": "xxx"}},
{$group: {_id: "$Comment.Reply.ip"}}
])

The result of example should be

/* 1 */
{
    "_id" : "192.168.1.1"
}

/* 2 */
{
    "_id" : "128.168.1.1"
}