PHP / MySQL - 以正确的格式准备字符串以插入日期时间SQL列

Question

In my UI the dates are shown like this - dd.mm.YYYY hh:ii:ss. The users are able to edit/add new dates and most probably they'll try to use the same format (24.06.2012 15:35:00) which can not be used for a SQL query. Here is what I've done till now:

$dt = (date_parse_from_format("d.m.Y H:i:s", $data['event_time']));
        $newdate = sprintf("%02d-%02d-%04d %02d:%02d:%02d" , $dt['day'], $dt['month'], $dt['year'], $dt['hour'], $dt['minute'], $dt['second']);
        $test = date("Y-m-d H:i:s", strtotime($newdate));
        if ($test == "1970-01-01 01:00:00")
        {
            throw new Exception('Invalid date');
        }

What happens is - if I leave the check if ($test == "1970-01-01 01:00:00") I get an exception, but if I comment the $test = date("Y-m-d H:i:s", strtotime($newdate)); line and the check the date is inserted only with zeros. $newdate is a sting in the right format for SQL - YYYY-mm-dd H:i:s but obv. I miss something here. How to insert this string as a valid SQL datetime?

Thanks

Leron