PHP INSERT INTO插入不了数据问题

提交表单用INSERT INTO插入数据，但总是空白，没提示出错。请问那里有问题了？

@header("content-Type: text/html; charset=utf-8");require_once 'inc/site_config.php';require_once 'inc/db_connections.php';require_once 'inc/function.php';mysql_query('set character set "utf8"'); session_start();if($_REQUEST['action']=='postreg'){$sql_check_usr="select * from `reguser`  where `UserId`='".$_SESSION['uid']."'";$info=mysql_query($sql_check_usr);$dingdanhao=date("YmjHis").$info[UserId];$spc=$_SESSION[producelist];$slc= $_SESSION[quatity];$shouhuoren=$_POST['trusername'];$dizhi=$_POST['address'];$youbian=$_POST['phone'];$tel=$_POST['mob'];$email=$_POST['email'];if(trim($_POST['d_content'])==""){   $leaveword=""; } else{   $leaveword=$_POST['d_content'];} $xiadanren=$_SESSION['uid']; $time=date("Y-m-j H:i:s"); $total=$_SESSION[total]; $sql_add_usr="INSERT INTO onlineorder  (dingdanhao,spc,slc,UserName,address,phone,mobile,mail,yqinfo,OrderTime,UserId,total_price) VALUES ('$dingdanhao','$spc','$slc','$trusername','$address','$phone','$mob','$email','$d_content','$time','$xiadanren','$total')";mysql_query($sql_add_usr);}	

回复讨论(解决方案)

把SQL语句打印出来，然后到PHPMYADMIN等工具中运行SQL语句看看结果如何。
这个是常用的检查SQL正确性方法。

$info=mysql_query($sql_check_usr);
$dingdanhao=date("YmjHis").$info[UserId];
$info 是个结果资源集，$info[UserId] 这样用不对

mysql_query($sql_add_usr) or die(mysql_error()); //这样看看是否报错