PHP / MySql - 检测值是否已分配的DateTime？

Question

I want to make an if statement that only runs if the datetime value is NOT null (0000-00-00 00:00:00)

I have passed the value via a query into a variable but how do i determine if it equals 0000-00-00 00:00:00?

$query = "SELECT * FROM stats WHERE member_id='" . $_SESSION['SESS_MEMBER_ID'] . "' "; 
$result = mysql_query($query);

while($row = mysql_fetch_array($result, MYSQL_ASSOC)) 
{
  $money = $row['money'];
  $bank_money = $row['bank_money'];
  $ap = $row['ap'];
  $exp = $row['exp']; 
  $last_ap_update = $row['last_ap_update'];
} 

if ($last_ap_update != ){ //Can i verify its NULL-ness here so i can run this if stament or run else?
}

Answer 1

Why not directly compare it :

if ($last_ap_update != "0000-00-00 00:00:00")
{
      //do whatever.
}