Definition
MongoDB\UpdateResult::getMatchedCount()Return the number of documents that were matched.
function getMatchedCount(): integer This method should only be called if the write was acknowledged.
Note
If an update/replace operation results in no change to the document (e.g. setting the value of a field to its current value), the matched count may be greater than the value returned by
getModifiedCount().
Return Values
The number of documents that were matched.
Errors/Exceptions
MongoDB\Exception\BadMethodCallException if this method is
called and the write operation used an unacknowledged write concern.