ผมจะ insert เวลาแบบกำหนดเอง ลงฐานข้อมูล ได้อย่างไรครับ

<select name="day" id="day" size="1">
<?php
for($d = 1; $d <= 31; $d++) {
echo "<option value=$d>$d</option>";
}
?>
</select>
<select name="month" id="month">
<?php
for($i = 1; $i <= 12; $i++) {
echo "<option value=$i>$i</option>";
}
?>
</select>
<select name="year" id="year">
<?php
$cur_year = date('Y');
$year1 = $cur_year;
$year2 = $cur_year + 1;

for($y = $year1; $y <= $year2; $y++) {
echo "<option value=$y>" . ($y + 543) . "</option>";
}
?>
</select>
<select name="hour" id="hour">
<option value="0">0</option>
<?
for($d=1;$d<=24;$d++)
{
?>
<option value="<? echo $d; ?>"><? echo $d; ?></option>
<?
}
?>
</select>
<select name="minute" id="minute">
<option value="0">00</option>
<?
for($i=1;$i<=59;$i++)
{
?>
<option value="<? echo $i; ?>"><? echo $i; ?></option>
<?
}
?>
</select>

<?
$end_date = $_POST['year'] . '-' . $_POST['month'] . '-' . $_POST['day'] . '-' . $_POST['hour'] . ':' . $_POST['minute'];
?>