MongoDB 中 PHP 的 mysqli_num_rows() 相当于什么？

Question

Specification

Database : MongoDB 3.4

Programming Language : PHP 7.1

Library : PHP library of MongoDB 1.2.0

Sample Code

$result = $connection->db->collection->find($filter, $options);

In MySQL, you do this:

$number_of_rows = mysqli_num_rows($result);

When trying things out and doing some research, I've tried this:

$number_of_rows = $result->count();

It returns this error since it's part of the legacy (not included in the MongoDB driver ):

Error: Call to undefined method MongoDB\Driver\Cursor::count()

When I tried using count() or sizeof(), the result is always 1.

$number_of_rows = count($result);

$number_of_rows = sizeof($result);

How should it be done properly in this version (or the latest version 3.6) of MongoDB without having to iterate a $count variable inside a for-loop?

Same question but outdated answers here .

Answer 1

I expanded @Yury-Fedorov's answer to these 3 options. I have tested this and it should work on your end.

Option 1

$filter = ['field' => 'value'];
$db = new \MongoDB\Driver\Manager('mongodb://localhost:27017');
$command = new \MongoDB\Driver\Command(['count' => $collection_name, 'query' => $filter]);
try {
    $cursor = $db->executeCommand($database_name, $command);
} catch (\MongoDB\Driver\Exception\Exception $e) {
    $error_message = $e->getMessage();
}
$count = $cursor->toArray()[0]->n;

Option 2

$filter = ['field' => 'value'];
$options = ['option' => 'value'];
$db = new \MongoDB\Driver\Manager('mongodb://localhost:27017');
$query = new \MongoDB\Driver\Query($filter, $options);
try {
    $cursor = $db->executeQuery("$database_name.$collection_name", $query);
} catch (\MongoDB\Driver\Exception\Exception $e) {
    $error_message = $e->getMessage();
}
$count = count($cursor->toArray());

Option 3

$filter = ['field' => 'value'];
$options = ['option' => 'value'];
$db = new \MongoDB\Client ('mongodb://localhost:27017');
try {
    $cursor = $db->{$database_name}->{$collection_name}->find($filter, $options);
} catch (\MongoDB\Driver\Exception\Exception $e) {
    $error_message = $e->getMessage();
}
$count = count($cursor->toArray());

Answer 2

You should be able to use $collection->count() method instead of $result->count() :

$query = []; // your criteria
$collection->count($query);

Take a look at this discussion or at my answer to another MongoDB count with PHP question, which is not exactly the same is this one.