Adding date of birth to database

Question

I'm trying to add fields for Day, Month and Year in registration form and add it to user record in database. So I've put this is the form:

<div class="form-group"> 
   <div class="form-inline">
      <div class="form-group pull-right">
         <select name="year" id="year" class="form-control">
            <option value="--" selected>Year</option>                       
            <?php
                for($i=date('Y'); $i>1899; $i--) {
                    $birthdayYear = '';
                    $selected = '';
                    if ($birthdayYear == $i) $selected = ' selected="selected"';
                    print('<option value="'.$i.'"'.$selected.'>'.$i.'</option>'."\n");
                }
            ?>                          
          </select>     
      </div>                    
      <div class="form-group pull-right">
        <select name="month" id="month" onchange="" class="form-control" size="1">
            <option value="--" selected>Month</option>
            <option value="01">Jan</option>
               ...
            <option value="12">Dec</option>
        </select>            
      </div>                                             
      <div class="form-group pull-right">
        <select name="day" id="day" onchange="" class="form-control" size="1">
        <option value="--" selected>Day</option>
        <option value="01">01</option>
                ...
        <option value="31">31</option>
      </select>
    </div>                                              
</div>
</div>  

Then in the php part this

if(!isset($error)){

    //hash the password
    $hashedpassword = $user->password_hash($_POST['password'], PASSWORD_BCRYPT);

    //create the activasion code
    $activasion = md5(uniqid(rand(),true));
    $dateOfBirth = $_POST['day']."-". $_POST['month']."-".$_POST['year'];

    try {
        $stmt = $pdo->prepare('INSERT INTO users (username,password,email,created,active,user_birthday) VALUES (:username, :password, :email, NOW(), :active, :user_birthday)');

        $stmt->execute(array(
            ':username' => $_POST['username'],
            ':password' => $hashedpassword,
            ':email' => $_POST['email'],                
            ':active' => $activasion,
            ':user_birthday' => $dateOfBirth
        ));
    ....

When I hit register everything is inserted into database but the date is 0000-00-00. It doesn't matter what I choose in dropdowns.

The field for user_birthday in database is DATE. Why doesn't save what is selected?

Answer 1

Database format for DATE is YYYY-MM-DD and you are trying to insert DD-MM-YYYY,

That is why its not inserting and taking default value: 0000-00-00.

Change:

$dateOfBirth = $_POST['day']."-". $_POST['month']."-".$_POST['year'];

To

$dateOfBirth = $_POST['year']."-". $_POST['month']."-".$_POST['day'];

Another approach:

Use array of $dateOfBirth

$dobArr = array($_POST['year'], $_POST['month'], $_POST['day']);
$dateOfBirth = implode('-', $dobArr);