Código PHP:
Ver original<?php
require_once('conexion.php');
$search = '';
if (isset($_POST['search'])){ $search = $_POST['search'];
}
$consulta = "SELECT * FROM alumnos WHERE nombre = '$search' ;
$resultado = $conexion->query($consulta);
?>
<?php if ($resultado>0 && $search!='') {?>
<h2>REGISTROS</h2>
<?php
echo "<table>";
echo "<tr>";
echo "<th>Nombre</th>";
echo "<th>edad</th>";
echo "<th>Pais</th>";
echo "</tr>";
echo "<tr>";
echo "<td>$fila['nombre']</td>";
echo "<td>$fila['apellido']</td>";
echo "<td>$fila['nit']</td>";
echo "</tr>";
}
echo "</table>"; ?>
<?php } ?>
prueba asi