MongoDB count with queries - mongodb

Question

I've been working on a project that now needs to use the MongoDB count function (MySQL equivalent's count function). The code I have at the moment is
$filter = ["username" => array('$ne' => null, '$ne' => '')];
$options = ["projection" => ['username' => true]];
$query = new MongoDB\Driver\Query($filter, $options);
$cursor = $mongo->executeQuery('mongodbLog.logs', $query);
I want to add the count functionality in the $filter array, but I can't get it to work correctly.
I want my MongoDB query to get the same result as this MySQL query: "SELECT username,count(*) FROM mysqlLog WHERE username <> '' GROUP BY username".
All I have managed so far is the where clause equivalent and now I'm stuck.

Answer 1

You can try the below aggregation.
Aggregation Stages - $match - $group - $project
$pipeline =
[
[
'$match' =>
[
'$and' =>
[
['username' => ['$ne' => null]],
['username' => ['$ne' => '']],
],
],
],
[
'$group' =>
[
'_id' => '$username',
'count' => ['$sum' => 1],
],
],
[
'$project' =>
[
'_id' => 0,
'username' => 1,
'count' => 1,
],
],
];
$command = new \MongoDB\Driver\Command([
'aggregate' => 'logs',
'pipeline' => $pipeline
]);
$cursor = $mongo->executeCommand('mongodbLog', $command);