I have an sql select query which is the following:

$sql = mysql_query("SELECT max(Price), Make, Model, Price FROM Used_Stock WHERE Make='$manufacturer' AND Feed_Id IN ('$feed_ident') GROUP BY Model ORDER BY Price ASC");

The $feed_ident is a variable which is set depending on which section of the site the user is in. The above query works fine if the variable is something like the following:
$feed_ident='11192'

The problem I have is that this variable will sometimes be more than one number ie:
$feed_ident='11192', '12345', '978685'

When this is the case the sql query fails.

Can anyone tell me how I can write the query above so that regardless of whether the variable is one value or a range of values the query will work please.

Thanks for any help in advance.