problem z kalendarzem Opcje

[luzny]

Witam mam następujące pytanie czy da się zrobić z tego kodu funkcje która skonwertuje mi daty do czytelnej postaci dla MySQLa i czy idzie zredukować powielanie kodu? Chciałbym móc wywołać ta funkcje w innym pliku i przeslać daty za pomocą $_GET?

Kod

   <form method="get" action="search.php" id="searchbar">
          
               <select name="startday">
                 <option value="" selected></option>
                 <?php for ($day=01; $day <= 31; $day++) {
                 ?>
                   <option value="<?php echo $day; ?>"><?php echo $day; ?></option>
                   <?php
                   }
                   ?>
                   </select>
                   <select name="startmonth">
                       <option value="" selected></option>
                       <option value="1">Styczen</option>
                       <option value="2">Luty</option>
                       <option value="3">Marzec</option>
                       <option value="4">Kwiecien</option>
                       <option value="5">Maj</option>
                       <option value="6">Czerwiec</option>
                       <option value="7">Lipiec</option>
                       <option value="8">Sierpien</option>
                       <option value="9">Wrzesien</option>
                       <option value="10">Pazdziernik</option>
                       <option value="11">Listopad</option>
                       <option value="12">Grudzien</option>
                   </select>
                   <select name="startyear">
                       <option value="2008" selected>2008</option>
                       <option value="2009" >2009</option>
                       <option value="2010" >2010</option>
                       <option value="2011" >2011</option>
                       <option value="2012" >2012</option>
                       </select>
                           <select name="endday">
                 <option value="" selected></option>
                 <?php for ($day=01; $day <= 31; $day++) {
                 ?>
                   <option value="<?php echo $day; ?>"><?php echo $day; ?></option>
                   <?php
                   }
                   ?>
                   </select>
                   <select name="endmonth">
                       <option value="" selected></option>
                       <option value="1">Styczen</option>
                       <option value="2">Luty</option>
                       <option value="3">Marzec</option>
                       <option value="4">Kwiecien</option>
                       <option value="5">Maj</option>
                       <option value="6">Czerwiec</option>
                       <option value="7">Lipiec</option>
                       <option value="8">Sierpien</option>
                       <option value="9">Wrzesien</option>
                       <option value="10">Pazdziernik</option>
                       <option value="11">Listopad</option>
                       <option value="12">Grudzien</option>
                   </select>
                   <select name="endyear">
                       <option value="2008" selected>2008</option>
                       <option value="2009" >2009</option>
                       <option value="2010" >2010</option>
                       <option value="2011" >2011</option>
                       <option value="2012" >2012</option>
                       </select>
                 <input id="searchbutton" class="submit" type="submit"
                   value="Szukaj">
             </form>