php - Error in SQL syntax when I try a query -

i've big (and stupid) problem simple sql insert query (mysqli), i've used format without errors, didn't work..

please me find problem..

//get admin form details $a_user = $_post["a_user"]; $a_pass = $_post["a_pass"]; $a_pin = $_post["a_pin"];  if($a_user == "$admin_username" && $a_pass == "$admin_password" && $a_pin == "$admin_pin"):     $keygen = md5(microtime().rand());     $mysqli->query("insert keys (keygen) values ('$keygen')") or die(mysqli_error($mysqli));     $mysqli->close; else:     header("location: ?page=admin&error=1"); endif; 

here error:

error: have error in sql syntax; check manual corresponds mysql server version right syntax use near 'keys (keygen) values ('85faa7f618e433819d7e5ca57076377c')' @ line 1

keys mysql reserved word http://dev.mysql.com/doc/refman/5.5/en/reserved-words.html

either wrap in backticks or use name it.

insert `keys` 

sidenote:

md5 old , considered broken if you're intending on using password purposes.

use crypt_blowfish or php 5.5's password_hash() function.
php < 5.5 use password_hash() compatibility pack.