How to Calculate Age from a Given Birth Date?

Extracting Age from Birth Date

In a database with user profiles that include birth dates, calculating age is essential. To convert a birth date into age in years, follow these steps:

Using PHP (>= 5.3.0)

• Object-Oriented Approach:

  <code class="php">$from = new DateTime('1970-02-01');
  $to   = new DateTime('today');
  echo $from->diff($to)->y;</code>

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• Procedural Approach:

  <code class="php">echo date_diff(date_create('1970-02-01'), date_create('today'))->y;</code>

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Using MySQL (>= 5.0.0)

<code class="sql">SELECT TIMESTAMPDIFF(YEAR, '1970-02-01', CURDATE()) AS age</code>

Sample PHP Code for Retrieving Age

Given the following PHP code to retrieve a user's birth date from a database:

<code class="php">if(isset($_GET['id']))
{
    $id = intval($_GET['id']);
    $dnn = mysql_fetch_array($dn);
    $dn = mysql_query('select username, email, skype, avatar, ' .
        'date, signup_date, gender from users where id="'.$id.'"');
    $dnn = mysql_fetch_array($dn);
    echo "{$dnn['date']}";
}</code>

To calculate the user's age from the retrieved birth date, you can modify the code as follows:

• Using Object-Oriented PHP:

  <code class="php">// Additional lines to calculate age
  $birthDate = new DateTime($dnn['date']);
  $today = new DateTime('today');
  $age = $birthDate->diff($today)->y;
  echo "{$age}";</code>

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• Using Procedural PHP:

  <code class="php">// Additional lines to calculate age
  $birthDate = date_create($dnn['date']);
  $today = date_create('today');
  $age = date_diff($birthDate, $today)->y;
  echo "{$age}";</code>

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