введите сю$servername = "XXX";
$username = "XXXXX";
$password = "XXXXXX";

$conn = new PDO("mysql:host=$servername;dbname=healthbot", $username, $password);
$conn->setAttribute(PDO::ATTR_ERRMODE, PDO::ERRMODE_EXCEPTION);


$stmt=$conn->prepare("select * from ".$tableName);
$stmt->execute();

$columnHeader ='';
$columnHeader = "[ИМЯ_КОЛОНКИ_1]"."t"."[ИМЯ_КОЛОНКИ_2]"."t"."[ИМЯ_КОЛОНКИ_3]"."t"."[ИМЯ_КОЛОНКИ_4]"."t";


$setData='';

while($rec =$stmt->FETCH(PDO::FETCH_ASSOC))
{
$rowData = '';
foreach($rec as $value)
{
    $value = '"' . $value . '"' . "t";
    $rowData .= $value;
}
  $setData .= trim($rowData)."n";
}


header("Content-type: application/octet-stream");
header("Content-Disposition: attachment; filename=Book record sheet.xls");
header("Pragma: no-cache");
header("Expires: 0");

echo ucwords($columnHeader)."n".$setData."n";да код