<?php
include_once("config.php");
$sql_query = "SELECT * FROM users LIMIT 10";
$resultset = mysqli_query($db, $sql_query) or die("database error:". mysqli_error($db));
$developer_records = array();
while( $rows = mysqli_fetch_assoc($resultset) ) {
    $developer_records[] = $rows;
}
if(isset($_POST["export_data"])) {
    $filename = "phpzag_data_export_".date('Ymd') . ".xls";
    header("Content-Type: application/vnd.ms-excel");
    header("Content-Disposition: attachment; filename="$filename"");
    $show_coloumn = false;
    if(!empty($developer_records)) {
      foreach($developer_records as $record) {
        if(!$show_coloumn) {
          // display field/column names in first row
          echo implode("t", array_keys($record)) . "n";
          $show_coloumn = true;
        }
        echo implode("t", array_values($record)) . "n";
      }
    }
    exit;
}
?>

header("Content-Type: application/vnd.ms-excel");
header("Content-Disposition: attachment; filename="$filename"");