Echo php code does not print anything

I am using following code to show in a table database results:

<table cellspacing="0" width="700">
    <tbody>
            <?php
            $sql = "SELECT id1, id2, id3, id4, id5 FROM table";
            $result = pg_query($db, $sql);
            if (pg_num_rows($result) != 0)
            {
                while($results_row = pg_fetch_row($result))
                {
                    echo '
                    <tr>
                        <td id="id1"> '.$results_row[1].'  </td>
                        <td id="id2"> '.$results_row[2].' </td>
                        <td id="id3"> '.$results_row[3].' </td>
                        <td id="id4"> '.$results_row[4].' </td>
                        <td id="id5"> ' if (.$results_row[5]. != "")
                                      {'.$results_row[5].'}' </td>

                    </tr>
                    ';
                }
            }
            ?>
    </tbody>
</table>

Obviously I'm having problems with "if" statement so nothing appears on the screen... Also I'd like to ask why dots are used in both sides of $results_row. Is it because it's an array?

---

One possible solution:

echo '
    <tr>
        <td id="id1"> '.$results_row[1].'  </td>
        <td id="id2"> '.$results_row[2].' </td>
        <td id="id3"> '.$results_row[3].' </td>
        <td id="id4"> '.$results_row[4].' </td>
        <td id="id5"> '; 

    if($results_row[5] != "")  { echo $results_row[5]; }

echo '
        </td>
    </tr>';