php - Form data is submitting, but isn't going into mySQL -

my db connection correct, able select , echo out rows of table. however, form data isn't updating database. i'm trying submit form on same page, left action blank. here php:

<?php if (isset($_post['submit'])) {      $con=mysqli_connect("localhost","hey","password!","dbname");     $sql="insert studentlist (studentnum, lastname, firstname, address, city, state, zip, balance, firsttermattended)     values('$_post[inputid]','$_post[inputlast]','$_post[inputfirst]','$_post[inputaddress]','$_post[inputcity]','$_post[inputstate]','$_post[inputzip]','$_post[inputbalance]','$_post[inputterm]')";     echo "it worked"; } ?> 

and here form:

   <form class="form-horizontal" role="form" method="post" action="">                 <div class="form-group">                      <div class="col-sm-offset-1 col-sm-10">                         <input type="text" class="form-control" id="inputid" placeholder="student id number">                     </div>                  </div>                   <div class="form-group">                      <div class="col-sm-offset-1 col-sm-10">                         <input type="text" class="form-control" id="inputlast" placeholder="last name">                     </div>                  </div>                  <div class="form-group">                      <div class="col-sm-offset-1 col-sm-10">                         <input type="text" class="form-control" id="inputfirst" placeholder="first name">                     </div>                 </div>                   <div class="form-group">                      <div class="col-sm-offset-1 col-sm-10">                         <input type="text" class="form-control" id="inputaddress" placeholder="street address">                     </div>                 </div>                   <div class="form-group">                      <div class="col-sm-offset-1 col-sm-10">                         <input type="text" class="form-control" id="inputcity" placeholder="city">                     </div>                 </div>                   <div class="form-group">                      <div class="col-sm-offset-1 col-sm-10">                         <input type="text" class="form-control" id="inputstate" placeholder="state">                     </div>                 </div>                    <div class="form-group">                      <div class="col-sm-offset-1 col-sm-10">                         <input type="text" class="form-control" id="inputzip" placeholder="zip">                     </div>                 </div>                  <div class="form-group">                      <div class="col-sm-offset-1 col-sm-10">                         <input type="text" class="form-control" id="inputbalance" placeholder="current balance">                     </div>                 </div>                   <div class="form-group">                      <div class="col-sm-offset-1 col-sm-10">                         <input type="text" class="form-control" id="inputterm" placeholder="first term attended">                     </div>                 </div>                    <div class="modal-footer">           <button type="button" class="btn btn-default" data-dismiss="modal">close</button>           <input type="submit" value="save student information" id="submit" name="submit" class="btn btn-primary">         </div>               </form> 

i have in header, screwing things up?

<?php // create connection $con=mysqli_connect("localhost","hey","password!","dbname");  // check connection if (mysqli_connect_errno())   {   echo "failed connect mysql: " . mysqli_connect_error();   } ?> 

your code missing mysqli_query , need assign name attribute input field. see sample example here http://www.w3schools.com/php/php_mysql_insert.asp