php - Avatar Upload Issue -

i'm scratching head, because can't figure out what's wrong code below.. $avatar_path not saved mysql table..

<?php  $avatar_path = $mysqli->real_escape_string('images/'.$_files['avatar']['name']);      //check if file type image     if (preg_match("!image!",$_files['avatar']['type'])) {          //copy image images/ folder          if (copy($_files['avatar']['tmp_name'], $avatar_path)){              //set session variables display on welcome page             $_session['username'] = $username;             $_session['avatar'] = $avatar_path;              //insert user data database              $update_row = $mysqli->query("update user_data set avatar='$avatar_path' user_id='1'") or die($mysqli->error());          }     } ?> 

could try ?

$update_row = $mysqli->query("update user_data set avatar='$avatar_path' user_id=1") or die($mysqli->error()); 

(i.e. suppress quotes around id value)* quotes not necessary around integers , possibly mess making mysql take string.