Mysql查询按月存储员工出勤率

How do I insert all employee attendance(Monthly once) in mysql database Here is my db tables

att_employee_id | att_year | att_month | att_present_days | att_absent_days |   att_workingdays

Date.prototype.daysInThisMonthOfThisYear=function() {
  return new Date(this.getFullYear(),this.getMonth()+1,0).getDate();
}
var days_inmonth = new Date().daysInThisMonthOfThisYear();

$(document).ready(function() {
    $( ".absent_days" ).keyup(function() {
         var days = $(this).val();
         $(this).closest("tr").find(".present_days" ).val( days_inmonth - days );   
        })  
});
<script src="https://ajax.googleapis.com/ajax/libs/jquery/1.8.3/jquery.min.js"></script>
<form name="emp_att" action="" method="post">
  <table>
    <thead>
      <tr>
        <th class="head0" style="width:5%">S.No</th>
        <th class="head1" style="width:15%">Employee ID</th>
        <th class="head0 no-sort" style="width:15%">No.of days present</th>
        <th class="head1 no-sort" style="width:15%">No.of days absent</th>
      </tr>
    </thead>
    <tbody>
      <tr>
        <td>1</td>
        <td>ETO0001</td>
        <td><input type="text" class="present_days" name="present_days" value=""></td>
        <td><input type="number" name="absent_days" class="absent_days" min="0" max="<?php echo date('t'); ?>" onChange="absentdays()" style="width:100%"></td>
      </tr>
      <tr>
        <td>2</td>
        <td>ETO0002</td>
        <td><input type="text" class="present_days" name="present_days" value=""></td>
        <td><input type="number" name="absent_days" class="absent_days" min="0" max="<?php echo date('t'); ?>" onChange="absentdays()" style="width:100%"></td>
      </tr>
      <tr>
        <td>3</td>
        <td>ETO0003</td>
        <td><input type="text" class="present_days" name="present_days" value=""></td>
        <td><input type="number" name="absent_days" class="absent_days" min="0" max="<?php echo date('t'); ?>" onChange="absentdays()" style="width:100%"></td>
      </tr>
      <tr>
        <td>4</td>
        <td>ETO0004</td>
        <td><input type="text" class="present_days" name="present_days" value="" readonly></td>
        <td><input type="number" name="absent_days" class="absent_days" min="0" max="<?php echo date('t'); ?>" onChange="absentdays()" style="width:100%"></td>
      </tr>
    </tbody>
  </table>
  <input type="submit" name="submit" value="Submit">
</form>

Here is my query to get all the employees

   <form name="emp_att" action="" method="post">
   <table>
   <thead>
   <tr>
    <th class="head0" style="width:5%">S.No</th>
    <th class="head1" style="width:15%">Employee ID</th>
    <th class="head0 no-sort" style="width:15%">No.of days present</th>
    <th class="head1 no-sort" style="width:15%">No.of days absent</th>
  </tr>
  </thead>
  <tbody>
    <?php
        $allemp= mysqli_query($con,"select * from t_emp e");
          $all_emp = mysqli_num_rows($allemp);

        if ($all_emp > 0)
        {
         $i=1;
            while($all_emp = mysqli_fetch_assoc($allemp))
          {
                 echo "<tr>";
                 echo "<td>".$i."<input type='hidden' name='serialno' value='".$i++."'></td>
                 <td> ".$all_emp["emp_id"]."</td>
                <td><input type='text' class='present_days' name='present_days' value=''></td>";
             echo "<td><input type='number' name='absent_days' class='absent_days' min='0' max= date('t') onChange='absentdays()' style='width:100%'></a></td>"; 
            echo "</tr>";
                 } 
          } 
        else 
        {
            echo "0 Results";
        }
        ?>
      </tbody>
      </table>
      <input type="submit" name="submit" value="Submit">
      </form>

Here I am getting all the n number of employees in the above form. when entered all employees "No.of days absent" and then hit on submit I am able to send only last record to the database. Can any one help me to send all the employees attendance to database Here is my form submission query

<?php
if(isset($_POST['submit']))
{ 
 $serialno=$_post['serialno'];
 $employee_id=$_post['emp_id'];
 $att_year = date('Y'); 
 $att_month = date('m'); 
 for($i=1; $i<= $serialno;$i++)
 {
  $present_days=$_POST['present_days'];
  $absent_days=$_POST['absent_days'];
  }
  $query=mysqli_query($con,"INSERT INTO t_emp_attendance(att_employee_id,att_year,att_month,att_present_days,att_absent_days)values('$employee_id','$att_year','$att_month','$present_days','$absent_days')");
  }
 ?>

any suggestions will be appreciated, I need to store all the employees attendance to database

</div>

Check you spelling for INSERT. And also you have missed to pass the connection object for inserting

First parameter should be the connection object in mysqli_*

mysqli_query(connectionObject,your Query);

$query=mysqli_query("INSERT INTO t_emp_attendance(att_employee_id,att_year,att_month,att_present_days,att_absent_days)values('$employee_id','$att_year','$att_month','$present_days','$absent_days')");


for($i=1; $i<= $serialno;$i++)
{
   $present_days=$_POST['present_days'][$i];
   $absent_days=$_POST['absent_days'][$i];
   $query=mysqli_query($con,"INSERT INTO t_emp_attendance(att_employee_id,att_year,att_month,att_present_days,att_absent_days)values('$employee_id','$att_year','$att_month','$present_days','$absent_days')");
}      

Your query should be inside the loop. And as suggested by parag, make text field names as arrays [] Soomething like this,

<input type="text" class="present_days" name="present_days[]" value="">
                                                          ^ ^

You shud do for all the text boxes.

Check that name of input fields are created. It might be overwritten with the latest values. Send it as an array format like "absent_days[]" it will solve your problem