Código PHP:
if($action == 'ajax'){
$q = mysqli_real_escape_string($con,(strip_tags($_REQUEST['q'], ENT_QUOTES)));
$aColumns = array('numero_factura','id_cliente_factura','nombre_cliente_factura');
$sTable = "facturas";
$sWhere = "";
if ( $_GET['q'] != "" )
{
$sWhere = "WHERE (";
for ( $i=0 ; $i<count($aColumns) ; $i++ )
{
$sWhere .= $aColumns[$i]." LIKE '%".$q."%' OR ";
}
$sWhere = substr_replace( $sWhere, "", -3 );
$sWhere .= ')';
}
$sWhere.=" order by id_cliente_factura asc";
include 'pagination.php';
$page = (isset($_REQUEST['page']) && !empty($_REQUEST['page']))?$_REQUEST['page']:1;
$per_page = 10;
$adjacents = 4;
$offset = ($page - 1) * $per_page;
$count_query = mysqli_query($con, "SELECT count(DISTINCT id_cliente_factura) AS numrows FROM $sTable $sWhere");
$row= mysqli_fetch_array($count_query);