<?php
header('Content-type: text/html; charset=utf-8');

$db_host="";
$db_user="";
$db_password="";
$db_name = "";
$mysqli = new mysqli($db_host, $db_user, $db_password, $db_name);
if (mysqli_connect_errno()) {
printf("Ошибка соединения: %sn", mysqli_connect_error());
exit;  }
$mysqli->set_charset("utf8");
if ($stmt = $mysqli->query('SELECT * FROM vtiger_contactdetails, vtiger_timesheet, vtiger_timesheetcf WHERE vtiger_contactdetails.contactid = vtiger_timesheet.cf_2295 AND vtiger_timesheet.cf_2295 = vtiger_timesheet.timesheetid')) {

while($row = $stmt->fetch_assoc()){
    echo $row['lastname'].' '.$row['cf_2295'].'<br />';
 }
 }

?>

SELECT * FROM vtiger_contactdetails
JOIN vtiger_timesheet
ON vtiger_contactdetails.contactid = vtiger_timesheet.cf_2295
JOIN vtiger_timesheetcf
ON  vtiger_timesheet.cf_2295 = vtiger_timesheet.timesheetid