Problem displaying an age based on a dateOfBirth mysql timestamp

I've got a site with user profiles. On the home page I am trying to show little summaries of each person's profile. This summary includes the name of the person, the gender and the age of the person.

        <ul>                
            {section name=i loop=$person_list}
                <li><a href="user_detail.php?id={$person_list[i].id}">{$person_list[i].username}, {$p开发者_Python百科erson_list[i].gender}, {$age[i]}
            {/section}
        </ul>

I previously used a foreach loop to run through them, but I need the index to also show the display age calculated in the index.php file.

if (isset($_GET['name']) && isset($_GET['gender'])) 
{
   $name = $_GET['name'];
   $gender = $_GET['gender'];
} 
else 
{
   $name = "";
   $gender = "";
}

define("PERSONS_PER_PAGE", 10);


if (isset($_GET['offset'])) 
{
    $offset = $_GET['offset'];
} 
else 
{
    $offset = 0;
}


list($person_list, $num_persons) = get_persons($name, $gender, $offset, PERSONS_PER_PAGE);

$ages = array();


for ($i = 0; $i < count($person_list); $i++)
{
    $ages[$i] = age($person_list[$i].$dateOfBirth, time());
}

$smarty = new Smarty;
$smarty->assign("name", $name);
$smarty->assign("gender", $gender);
$smarty->assign("persons_per_page", PERSONS_PER_PAGE);
$smarty->assign("interests", $interests);
$smarty->assign("offset", $offset);
$smarty->assign("num_persons", $num_persons);
$smarty->assign("person_list", $person_list);
$smarty->assign("ages", $ages);
$smarty->display("index.tpl");

Don't worry too much about the $offset and PERSONS_PER_PAGE, that's only used for pagination.

My age function looks like this:

function age($birth)
{
   $birth_date = new DateTime();
      $birth_date = $birth;
   $birth_date->setTimestamp($birth);

   $now = time();

   $now_date = new DateTime();
   $now_date->setTimestamp($now);

   $interval = $birth_date->diff($now_date); // $interval is a DateInterval


   $age = $interval->y; // number of years in the interval
   return $age;
}

Additionally, in case it's relevant; my get_persons function looks like this:

function get_persons($name, $gender, $offset, $persons_per_page) 
{
    $connection = mysql_open();

    $query = "SELECT SQL_CALC_FOUND_ROWS id, username, gender, dateOfBirth FROM Person";
    if ($name && $gender) 
    {
        $query .= " WHERE name like '%$name%' AND gender like '%$gender%'";
    }
    $query .= " order by id";
    $query .= " LIMIT $offset, $persons_per_page";
    // print "$query<br>\n";

    $result = mysql_query($query, $connection) or show_error();

    $r = mysql_query("SELECT FOUND_ROWS()", $connection) or showerror();
    $r = mysql_fetch_array($r);
    $num_entries = $r[0];

    $entries = array();

    $person_list = array();
    while ($person = mysql_fetch_array($result)) {
        $person_list[] = $person;
    }

    mysql_close($connection) or show_error();
    return array($person_list, $num_entries);
}

and the table for a person looks like this:

create table if not exists Person
(
  id int not null auto_increment primary key,
  username varchar(10) not null,
  name varchar(40) not null,
  gender varchar(1) not null,
  dateOfBirth timestamp not null,
  email varchar(40) not null
);

This produces the following error:

Notice: Undefined variable: dateOfBirth in /net/homes.ict.griffith.edu.au/export/home/s2737451/public_html/wp/labs/lab5/index.php on line 39 Fatal error: Call to a member function setTimestamp() on a non-object in /net/homes.ict.griffith.edu.au/export/home/s2737451/public_html/wp/labs/lab5/includes/defs.php on line 167

Thanks in advance, I really need help on this :(

I think that prodigitalson solved your problem, but there are some miscellanous suggestions for your code:

• Your SQL query is vunerable to SQL Injection attacks. This is because you are directly inserting user input (GET parameters) into your SQL query string--a big NO NO. For string values, you should use a string escape function, which ensures the string is inserted safely into the query. For MySQL, use the mysql_escape_string() function:

  $query .= " WHERE name like '%" . mysql_escape_string($name) . "%' AND gender like '%" . mysql_escape_string($gender) . "%'";
  

  For numeric values, you should check to make sure the user entered a number and not something else like letters. You probably want $offset to always be a positive number, so you can use the ctype_digit() function to make sure the variable contains only number characters (0-9). The value of $persons_per_page is hard-coded in your script, so you don't have to worry about it.

  if (!ctype_digit($offset)){
     //set to a default value if it's not a positive integer
     $offset = 10;
  } 
  $query .= " LIMIT $offset, $persons_per_page";
  

• You can simplify the code that calculates the number of person entries that were returned. Make use of the mysql_num_rows() function:

  $num_entries = mysql_num_rows($result);
  

Update:

I tried that but it still gave me the error: Fatal error: Call to a member function setTimestamp() on a non-object in /net/homes.ict.griffith.edu.au/export/home/s2737451/public_html/wp/labs/lab5/inc­ludes/defs.php on line 167

I think that is because youre overwriting your DateTime object:

$birth_date = new DateTime();
$birth_date = $birth; // you overwrite the instance of DateTime you created with another value
$birth_date->setTimestamp($birth);

should be:

$birth_date = new DateTime();
$birth_date->setTimestamp($birth);

Like the error says you try to use the variable $dateOfBirth when it hasnt been defined:

$ages[$i] = age($person_list[$i].$dateOfBirth, time());

I think th issue is you have confused your smarty and php syntax... that line should probably be:

$ages[$i] = age($person_list[$i]['dateOfBirth'], time());

On another note why do you use a seperate array for age why not just add that element to the array of values for each person?

foreach($person_list as $i => $person)
{
    $person_list[$i]['age'] = age($person['dateOfBirth'], time());
}

or you can do it by changing your sql command:

function get_persons($name, $gender, $offset, $persons_per_page) 
{
    $connection = mysql_open();

   $query = "SELECT SQL_CALC_FOUND_ROWS id, username, gender, (YEAR(NOW())-YEAR(dateOfBirth)) as age FROM Person";
    if ($name && $gender) 
    {
        $query .= " WHERE name like '%$name%' AND gender like '%$gender%'";
    }
    $query .= " order by id";
    $query .= " LIMIT $offset, $persons_per_page";

    $result = mysql_query($query, $connection) or show_error();

    $r = mysql_query("SELECT FOUND_ROWS()", $connection) or showerror();
    $r = mysql_fetch_array($r);
    $num_entries = $r[0];

    $entries = array();

    $person_list = array();
    while ($person = mysql_fetch_array($result)) {
        $person_list[] = $person;
    }

    mysql_close($connection) or show_error();
    return array($person_list, $num_entries);
}