Searching script problem

[tua1]

Hello!

I have a problem with my searching script.

My html form:

     <form id="frmPokaz" action="pokaz.php" method="post" >
	  <fieldset id="Pokaz"><legend>Wybierz swoja kategorie</legend><table id="tblPokaz" >
	   <tr>
	    <td class="underline">Dyscyplina:</td>
	    <td>
         <select name="dyscyplina" id="select">
	     <option selected value="0"><strong>Wszystkie</strong></option>
	     <option value="1">Koszykówka</option>
	     <option value="2">Pilka Nozna</option>
	     <option value="3">Sztuki walki</option>
	     <option value="4">Lekkoatletyka</option>
	     <option value="5">Terefere</option>
	     <option value="6">Biegi</option>
	     <option value="7">Suplementy</option>
	     </select>	   </td>
	   <td class="underline"> Kategoria:	   </td>
	   <td>Odziez	 </td>
	   <td>
	    <input name="kategoria" type="checkbox"  class="checkbox" value="1" >	   </td>  

	   <td>Sprzet</td>
	   <td><input name="kategoria" type="checkbox" class="checkbox" value="2">	   </td>
	   <td>Inne</td>
	   <td><input name="kategoria" type="checkbox"  class="checkbox" value="3"  >	   </td>
	   <td><input type="submit" class="submit" name="submit" id="pokaz" value="Pokaz"></td>
	   </tr>

   </table></fieldset>
  </form>

My php script:

  [code]<?php

require_once ("include/polaczenie.php");

//$_POST['kategoria']= array();

foreach ($_POST['kategoria'] as $pt) {
$in1 .= "'" . $pt . "',";

}
$in1 = substr($in1,0,strlen($pt)-1);

$sql = "select ID_prod, ID_kat, ID_dyscyplina, nazwa_prod, cena, dostepny, opis_prod from produkty where ID_kat IN (" . $in1 . ") and ID_dyscyplina=" . $_POST['dyscyplina'] . ";";
//echo $sql;

$query = mysql_query($sql);

while ($row = mysql_fetch_array($query)) {
echo '<p class="p_account_php">',$row['nazwa_prod'],'</p> ',$row['nazwa_prod'];
}

?>[/code]

The error is:

Warning: mysql_fetch_array(): supplied argument is not a valid MySQL result resource in C:\WebServ\httpd\Runners2\pokaz.php on line 241

Could anyone help?

Regards

[leatherback]

It tells you that the query which you ran is invalid, or that there was no connection to the database. I presume the most common: You have an error in your query.

As error-handling to your queries, and test whether a query resulted in valid data to debug these things yourself:

// Note that using $query here is fconfusing. Better would be to use $result, ast the outcome of the mysql_query is a result set.

$query = mysql_query($sql) or die(mysql_error());
if(mysql_num_rows($query) > 0)
  {
  echo 'We have results';
  }