[SOLVED] building dynamic query

[xiao]

I have this query:

$qry = mysql_query("SELECT p.products_id, p.products_model, p.products_price, pd.products_name FROM products p, 
products_description pd, products_to_categories pc WHERE p.products_id = pd.products_id AND pd.language_id = '".$instT."' GROUP BY 
pd.products_name ORDER BY p.products_price") or die(mysql_error());

But I need some "AND PC.categories_id = $variable" in it like this:

foreach($instV400 as $voedingCat){
     echo "AND pc.categories_id = '".$voedingCat."' ";
}

 

So it should look somewhat like this:

$qry = mysql_query("SELECT p.products_id, p.products_model, p.products_price, pd.products_name FROM products p, 
products_description pd, products_to_categories pc WHERE p.products_id = pd.products_id AND pd.language_id = '".$instT."' " .
foreach($instV400 as $voedingCat){
echo "AND pc.categories_id = '".$voedingCat."' ";
}	
. "GROUP BY pd.products_name ORDER BY p.products_price") or die(mysql_error());

 

But I have no idea how to build a query like that  :-\