How to get users with birthday today in plugin/module?
Was able to get the results I needed by using the following query: 

        $users = \craft\elements\User::find()
            -&gt;where("extract(day from content.field_birthdate) = " . date('j'))
            -&gt;andWhere("extract(month from content.field_birthdate) = " . date('n'))
            -&gt;group('siteUsers')
            -&gt;status('active')
            -&gt;all();