view of query in mongodb - mongodb

Question

I have a collection ,this is one of it's docs :
{
"_id" : 1 ,
"first_name" : "john",
"phone" : [
{
"type" : "mobile",
"number" : "9151112233"
},
{
"type" : "home",
"city_code" : 51,
"number" : "55251544"
},
{
"type" : "mobile",
"number" : "9152425125"
}
]
}
I'm searching for "phones" that contain type "mobile" and show them.
I need something like this :
{
"number" : "9151112233",
"number" : "9152425125"
}
I write this query for that :
db.main.find({ _id : 1 , 'phone.type' : "mobile" },{'phone.number' : true , _id : false}).forEach(printjson)
I want to show only numbers that their types are mobile but this query show all to numbers because this single doc contain others too.
How can I fix it?

Answer 1

I'd use the aggregation framework along with the $unwind, $match and $project commands. This:
db.main.aggregate({$unwind:"$phone"},{$match:{"phone.type":"mobile"}},{$project:{"phone.number":1,"_id":0}})
produces this output:
{ "phone" : { "number" : "9151112233" } }
{ "phone" : { "number" : "9152425125" } }
which only matches the mobile numbers.
http://docs.mongodb.org/manual/aggregation/