mongodb Join two collections to get data - php

Question

So here is my attempt it did not work, I am not sure what I need to do, and the docs explaining this are just confessing.
so I am hoping someone on here knows how to do this.
Basic concept: I have stored the users latest profile picture ID in the users main profile collection
members collection
{
"_id" : ObjectId("aaaat656a464"),
"email" : "russell#ipet.xyz",
"personal" : {
"name" : {
"firstname" : "Russell",
"lastname" : "Harrower"
},
"profile_id" : ObjectId("333a0e2b7acebe9b869b1b0a")
},
"kst" : ObjectId("111111111111g")
}
Now I want to get that profile_id from members_media collection which _id = profile_id
This is the members_media collection
{
"_id" : ObjectId("333a0e2b7acebe9b869b1b0a"),
"data" : {
"url" : "https://scontent.xx.fbcdn.net/v/t1.0-1/11659354_1625058617782022_7822649569017662262_n.jpg?oh=6e2b74b33c1c4ea4cdc0094a1ae35e14&oe=59DF809A",
"type" : "facebook/image",
"date" : ISODate("2017-06-21T06:16:18.580Z"),
"profile_pic" : true
},
"uid" : ObjectId("111111111111g")
}
So here is my attempt
$check = $db->aggregate([
['$unwind'=> "$members_media"],
['$unwind' => ['path'=>"$members_media", 'includeArrayIndex'=>"arrayIndex"]],
['$lookup'=>
[
'from'=>"members_media",
'localField'=>"personal.profile_id",
'foreignField'=>"_id",
'as'=>"profilepic"
]
]
]);
However when I run the following it does not get the members collection
$db = static::db()->members;
/*$check = $db->findOne(['kst' => New MongoDB\BSON\ObjectId($_SESSION["ipet_user"]), 'personal'=>['$exists'=>true]],
['personal.profile_id' => 1]
);*/
$check = $db->aggregate([
['$lookup' =>
[
'from'=>"members_media",
'localField'=>"members.personal.profile_id",
'foreignField'=>"_id",
'as'=>"data"
]
],
['$match' =>
['members.kst' => New MongoDB\BSON\ObjectId($_SESSION["user"]), 'members.personal'=>['$exists'=>true]]
],
['$unwind' => ['path' => '$members_media.data', 'includeArrayIndex' => 'arrayIndex']],
['$project' =>
['members.profile_path'=>'$data.url']
]
]);
my result is
object(MongoDB\Driver\Cursor)#19 (9) { ["database"]=> string(4) "ipet" ["collection"]=> NULL ["query"]=> NULL ["command"]=> object(MongoDB\Driver\Command)#18 (1)

Answer 1

We can do like this
$resultData = $db->collectionName->aggregate([
['$lookup' => [
'from' => 'members_media',
'localField' => 'personal.profile_id',
'foreignField' => '_id',
'as' => 'profileDetail',
]]]);
$myData = array();
foreach($resultData as $result) {
//var_dump($result);
array_push($myData, $result);
}
print_r($myData);