Remove duplicates from drop down list

Question

I'm using the code below to return a list of LastNames into a form's drop down menu.

<?php
    include 'conn.inc.php';
    $sql_dropdown_lastname = "SELECT LastName FROM Individuals";
    $sql_run_lastname = odbc_exec($conn_general, $sql_dropdown_lastname);
        echo "<table><form action='index.php' method='POST'><tr><td>Individual Last Name</td><td><select name='IndivSurname'>";
            while($lastname_row = odbc_fetch_array($sql_run_lastname)){
                $AllLastName=$lastname_row['LastName'];
                    echo"<option value='$AllLastName'>$AllLastName</option>";
            }

        echo"</select></td>
                </tr>
                <tr>
                    <td><input type='submit' value='submit' name='submit'></td>
                </tr>
                </form>
        </table>";

?>

However several entries are duplicate. How would I be able to eliminate any duplicates from the drop down list ?

Thanks in advance, J

Answer 1

If they are truly duplicates (and not just people with the same last name), you can do it like this:

SELECT DISTINCT LastName FROM Individuals

Note, if they are people who are different, but have the same last name, you'd want to bring in another field in your query, such as this:

SELECT DISTINCT LastName, FirstName FROM Individuals