I have some data that looks like this:
[
{
\"_id\" : ObjectId(\"4e2f2af16f1e7e4c2000000a\"),
\"advertisers\" : [
{
Use dot notation (e.g. advertisers.name
) to query and retrieve fields from nested objects:
db.agencies.find({
"advertisers.created_at": {
$gte: start,
$lt: end
}
},
{
_id: 1,
program_ids: 1,
"advertisers.name": 1
}
}).limit(1).toArray();
Reference: Retrieving a Subset of Fields and Dot Notation
There is one thing called dot notation that MongoDB provides that allows you to look inside arrays of elements. Using it is as simple as adding a dot for each array you want to enter.
In your case
"_id" : ObjectId("4e2f2af16f1e7e4c2000000a"),
"advertisers" : [
{
"created_at" : ISODate("2011-07-26T21:02:19Z"),
"category" : "Infinity Pro Spin Air Brush",
"updated_at" : ISODate("2011-07-26T21:02:19Z"),
"lowered_name" : "conair",
"twitter_name" : "",
"facebook_page_url" : "",
"website_url" : "",
"user_ids" : [ ],
"blog_url" : "",
},
{ ... }
If you want to go inside the array of advertisers to look for the property created_at inside each one of them, you can simply write the query with the property {'advertisers.created_at': query} like follows
db.agencies.find( { 'advertisers.created_at' : { {$gte : start , $lt : end} ... }
db.agencies.find(
{ "advertisers.created_at" : {$gte : start , $lt : end} } ,
{ program_ids : 1 , advertisers.name : 1 }
).limit(1).pretty();