How do I remove the comma if there is no value?

I have a select field that gets its values from a database table. Not all records in the database have all fields. Some are null. I want my select field to show the name,iata,icao – a combination of these three seperated by a comma. The issue is that some of my fields do not have an icao and some do not have an iaata. Is there a way for me to alter my code such that if there is no icao or iata the comma is ignored.

Please see below:

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The code i need to alter is below:

 <select name="airport1" class="airport1" id="airport1">
                    <option selected value="Add">Select Airport</option>

                    <?php
                    $mysqli = NEW MYSQLI("localhost", "root", "", "airports");
                    $resultSet = $mysqli->query("SELECT name,iata,icao 
    FROM airports order by name ASC;
    ");

?>

                    <?php
                    while ($rows = $resultSet->fetch_assoc()){
                        $name = $rows['name'];
                        $iata = $rows['iata'];
                        $icao = $rows['icao'];
                        echo "<option value='$name,$iata,$icao'>$name,$iata,$icao</option>";
                    }
?>