在MySQL中将日期POST到datetime的正确方法

Question

I have created a form that sends data to a database, all fields are working except date, i assume it is to do with the format but i am unsure how to go about it?

HTML

<dt>Date of Purchase</dt>
        <dd>
            <select id="date_of_purchase" name="entry[date_of_purchase]">
            <option value="">Month</option>
            <option value="Jan">Jan</option>
            <option value="Feb">Feb</option>
            <option value="Mar">Mar</option>
            </select>
            <select id="date_of_purchase" name="entry[date_of_purchase]">
            <option value="">Day</option>
            <option value="1">1</option>
            <option value="2">2</option>
            <option value="3">3</option>
            <option value="4">4</option>
            </select>
            <select id="date_of_purchase" name="entry[date_of_purchase]">
            <option value="">Year</option>
            <option value="2013">2013</option>
            <option value="2014">2014</option>
            <option value="2015">2015</option>
            <option value="2016">2016</option>
            </select>
    </dd>

PHP

$stmt = DB::query(Database::INSERT, 'INSERT INTO `registration` (`first_name`, `last_name`, `date_of_purchase`) VALUES (:first_name, :last_name, :date_of_purchase)');                  

$stmt->param(':first_name', $post['first_name']);
$stmt->param(':last_name', $post['last_name']);
$stmt->param(':date_of_purchase', $post['date_of_purchase']);

Answer 1

you should use different names for fields

<dt>Date of Purchase</dt>
        <dd>
            <select id="month_of_purchase" name="month_of_purchase">
            <option value="">Month</option>
            <option value="Jan">Jan</option>
            <option value="Feb">Feb</option>
            <option value="Mar">Mar</option>
            </select>
            <select id="day_of_purchase" name="day_of_purchase">
            <option value="">Day</option>
            <option value="1">1</option>
            <option value="2">2</option>
            <option value="3">3</option>
            <option value="4">4</option>
            </select>
            <select id="year_of_purchase" name="year_of_purchase">
            <option value="">Year</option>
            <option value="2013">2013</option>
            <option value="2014">2014</option>
            <option value="2015">2015</option>
            <option value="2016">2016</option>
            </select>
    </dd>

and then construct date as

$stmt->param(':date_of_purchase', sprintf("%d-%d-%d", $post['day_of_purchase'], $post['month_of_purchase'], $post['year_of_purchase']));

(i assume that $post['year_of_purchase'] is the same as $_POST['year_of_purchase'])