如何学习Sphinx以各种日期时间格式进行搜索？

I have database table with two DATETIME fields and multiple text fields aswell. Those DATETIME's are stored in Mysql valid format e.g. "2015-04-16 10:41:44". But I need to search it in europe time format e.g. "16.4.2015" should return previous example's row.

Here's my code:

$sphinx = new SphinxClient();
$sphinx->SetServer('localhost', 9312);
$result = $sphinx->Query($string, 'myindex', "Search was performed on string '".$string);

and here is part of my sphinx config file:

sql_query_pre = SET NAMES utf8
sql_query = \
    SELECT id, worked, username, clientName, rate, period, subjectOfWork, comment, UNIX_TIMESTAMP(since) AS since, UNIX_TIMESTAMP(until) AS until \
    FROM timerecords
sql_attr_timestamp = since
sql_attr_timestamp = until

Thanks for your advices.