您缺少一个值.

对于这么长的查询，如果有这么多的列(如果只插入一行)，我建议使用以下INSERT语法，该语法更易于阅读，并且不太可能引起问题.

For queries this long with so many columns (and if you're inserting just one row), I'd suggest using the following INSERT syntax, which is much easier to read and less likely to cause problems.

$query = "INSERT INTO users_tb SET
          user_status    = '". mysql_real_escape_string($status) ."',
          user_gender    = '". mysql_real_escape_string($gender) ."',
          user_firstname = '". mysql_real_escape_string($firstname) ."',
          user_surname   = '". mysql_real_escape_string($surname) ."',
          student_number = '". mysql_real_escape_string($hnumber) ."',
          user_email     = '". mysql_real_escape_string($email) ."',
          user_dob       = '". mysql_real_escape_string($dob) ."',
          user_name      = '". mysql_real_escape_string($username) ."',
          user_pass      = '". mysql_real_escape_string($password) ."'";
mysql_query($query) or die(mysql_error());
mysql_close();