guys i wrote a dropdown bar connected to a db, but i couldnt make the content of the table thats fetched from db only specified by the option i chose in drop bar, how can i fix this

here’s my code:

$sql = "SELECT CPTE FROM comana";
$stmt = oci_parse($conn, $sql); 

oci_execute($stmt);

while ($row = oci_fetch_assoc($stmt)) {
    echo "<tr>n";
    echo "<td>" . ($row['CPTE'] !== null ? htmlentities($row['CPTE'], ENT_QUOTES) : '') . "</td>n";
    echo "</tr>n";
}
    echo "</table>n";

i want the table to only fetch the selected option data