1054 where子句中的未知列？

Question

i am updating my table employer with the following details but it is showing above error while updating

  <?php  

      $name=$_POST['name'];
      $phone=$_POST['phone'];
      $lname=$_POST['lname'];
      $stmt = $db->prepare("UPDATE employer 
     SET name='.$name.', phone='.$phone.',lname='.$lanme.' 
      WHERE username=".$_SESSION['username']." ");
      ?>

Answer 1

Query Statement is not properly concatenated. This is the issue:

 $stmt = $db->prepare("UPDATE employer 
     SET name='".$name."', phone='".$phone."',lname='".$lanme."' 
      WHERE username='".$_SESSION['username']."' ");