php-mongodb

Below query worked fine in Studio 3T and Robomongo, But I want to convert it into PHP format, Following is my query, db.news.aggregate([ { $match: { "_id" : "1" } }, { "$project": { "comments": { "$filter": { "input": "$comments", "as": "comment", "cond": { "$eq": [ "$$comment.status", "active" ] } } } } }, { "$project": { "comments": { "$slice": [ { "$slice": [ "$comments", { "$subtract": [ { "$size": [ "$comments" ] }, 1 ] } ] }, -1 ] } } }]) I have tried below, But it giving error " Error: localhost:27017: FieldPath field names may not be empty strings. " PHP converted sample: <?php

This question already has an answer here: $unwind empty array 2 answers I am performing aggregation on employees table to fetch some hostel details with projection like $query = ['_id' => new MongoDB\BSON\ObjectID($this->EmployeeId)]; $pipeline = array( ['$match' => $query], [ '$addFields'=> [ 'assigned_master_keys'=> [ '$cond'=> [ 'if'=> [ '$ne'=> [ [ '$type'=> '$assigned_master_keys' ], 'array' ] ], 'then'=> [], 'else'=> '$assigned_master_keys' ] ] ]], ['$unwind'=> '$assigned_master_keys'], ['$lookup' => [ 'from' => 'HostelTbl', 'let' => [ 'hostelid' => '$assigned_master_keys.hostel_id' ],

I have updated mongo and now in the log the following error appears: Use of the aggregate command without the cursor option is deprecated Mongo says that I should put a second REQUIRED parameter to aggregate function, because my current usage is deprecated. I currently use the following code PHP (now is deprecated): $this->db->{$collection}->aggregate($options); And return this format: {"result":[ { "_id":"xxxxxx", "update":[ { "firstUpdateTime":xxxxxx, "updateTime":xxxxxxx, } ], "media":[ { "xxxx":{ ... To not use an deprecated code I add the new second parameter (but I do not understand what