Search in multiple columns using a html form

Working CODE :)

Is this the right way to do this? or am i missing some more security code??

What went wrong? the first if condition was: if (isset($_POST['submit']) {

The code..

}

i don't know how but it wouln'd work liek that, so i changed it to the code below and now it works!! :)

<?php

                    if (isset($_POST['username']) || isset($_POST['locatie']) || isset($_POST['geslacht']) || isset($_POST['online'])) {

                        $name = mysqli_real_escape_string($server, $_POST['username']); 
                        $waar = mysqli_real_escape_string($server, $_POST['locatie']);
                        $sex = mysqli_real_escape_string($server, $_POST['geslacht']);  
                        $status = mysqli_real_escape_string($server, $_POST['online']);

                        $sql= "SELECT * FROM users WHERE 1=1";
                            if (isset($_POST['username'])) {
                                $name = $_POST['username'];
                                $sql .= " and username LIKE '%$name%'";
                            }

                            if (isset($_POST['locatie'])) {
                                $name = $_POST['locatie'];
                                $sql .= " and locatie LIKE '%$waar%'";
                            }

                            if (isset($_POST['geslacht'])) {
                                $name = $_POST['geslacht'];
                                $sql .= " and geslacht LIKE '%$sex%'";
                            }

                            if (isset($_POST['online'])) {
                                $name = $_POST['online'];
                                $sql .= " and online LIKE '%$status%'";
                            }

                                $sql .= " ORDER BY RAND()";

                        $result_set=mysqli_query($server,$sql) or die(mysqli_error($server));

                            //echo $sql;
                            echo '<div class="col-sm-12">';

                        while($row=mysqli_fetch_array($result_set)) {
                            echo '<div class="col-sm-2">';
                            echo '<center><img class="img-vrienden" src=' . $row['prof_pic'] . ' /><br>' . $row['username'].'</center>';
                            echo '</div>';
                        }
                            echo '</div>';   
                    }
                ?>