Выборка по одному из 3 критериев

 <form method="post" action="filter.php">
        <p>Find student by</p>
        <table>
            <tr><td>Insurance Number</td><td><input type="text" name="InsuranceNumber"/></td></tr>
            <tr><td>Surname</td><td><input type="text" name="Surname"/></td></tr>
            <tr><td>Year of birth</td><td><input type="text" name="YearOfBirth"/></td></tr>
        </table>
        <input type="submit" name = "submit" value="Submit"/>
    </form>
    <table style="table">
    <tr><th width=10%>Insurance number</th><th width=10%>Surname</th><th width=10%>Name</th><th width=8%>Year of birth</th><th width=10%>City of birth</th><th width=18%>Univercity</th></tr>
    <?php
    include_once("db.php");
    if (isset($_POST['submit']))
    {
        $IN = strip_tags(trim($_POST['InsuranceNumber']));
        $SN = strip_tags(trim($_POST['Surname']));
        $YB = strip_tags(trim($_POST['YearOfBirth']));
        $result = mysql_query(" SELECT * FROM students
                                WHERE (InsuranceNumber = '$IN'
                                OR Surname = 'SN'
                                OR YearOfBirth] = '$YB')
                                ORDER BY Surname "); }
        while ($content = mysql_fetch_assoc($result)){
        ?>