insert query wont insert date using drop down list

I have have a drop down list which meant to insert date of birth into database cloumn name date_of_birth bt is not wrking it inserts all the data except tha column help what am doing wrong????

$date_of_birth = $_POST['year_of_birth'] . '-' . $_POST['month_of_birth'] . '-' . $_POST['day_of_birth'];

$q = "INSERT INTO driversnew (id, name, location, date_of_birth, car_number,

   favourite_track, least_favourite_track, achievements, sponsors, email, image, display)

VALUES ('$_POST[id]', '$_POST[name]', '$_POST[location]','$date_of_birth','$_POST[car_number]','$_POST[favourite_track]', '$_POST[least_favourite_track]','$_POST[achievements]', '$_POST[sponsors]','$_POST[email]', '$image_name','0')";

$rs = mysql_query($q) or die("Problem with the query: $q<br>" . mysql_error()); 

PHP:

this the form

<?php

$months = array('','January','February','March','April','May','June','July','August','September','October','November','December');

echo '<select name="month_of_birth">';

for ($i=1;$i<13;++$i) {

   echo '<option value="' . sprintf("%02d",$i) . '">' . $months[$i] . '</option>';

}

echo '</select>';

echo '<select name="day_of_birth">';

for ($i=1;$i<32;++$i) {

   echo '<option value="' . sprintf("%02d",$i) . '">' . $i . '</option>';

}

echo '</select>';

echo '<select name="year_of_birth">';

$year = date("Y");

for ($i = $year;$i > $year-50;$i--) {

   $s = ($i == $year)?' selected':'';

   echo '<option value="' . $i . '" ' . $s . '>' . $i . '</option>';

}

echo '</select>';

?>

PHP:

 

You don't say what format the date_of_birth column is in. Is it date/datetime or unix timestamp. I suspect that the format of the date that you are attempting to insert is wrong

 

date_of_birth is this date field or datetime field in database ?

u can see date /datetime row insertion like this INSERT INTO test (`date` ,`datetime`) VALUES ('2010-09-08', '2010-09-10 17:12:10');

 

hi i manage to get the insert date to work bt now the problems is how to keep the value of the drop dwon lists i know how to keep am input but how do i keep for the options list??

$months = array('','January','February','March','April','May','June','July','August','September','October','November','December');

echo '<select name="month_of_birth">';

for ($i=1;$i<13;++$i) {

   echo '<option value="' . sprintf("%02d",$i) . '">' . $months[$i] . '</option>';

}

echo '</select>';

echo '<select name="day_of_birth">';

for ($i=1;$i<32;++$i) {

   echo '<option value="' . sprintf("%02d",$i) . '">' . $i . '</option>';

}

echo '</select>';

echo '<select name="year_of_birth">';

$year = date("Y");

for ($i = $year;$i > $year-50;$i--) {

   $s = ($i == $year)?' selected':'';

   echo '<option value="' . $i . '" ' . $s . '>' . $i . '</option>';

}

echo '</select>';

PHP: