Oh, I see what you want. Yeah, you can't expect two databases to be able to share a single database connection. However, you can get the results you want using something like the (untested) bit below:

$dbh1->connect("to db2 database"); 
$dbh2->connect("to sybase database"); 
$sth1=$dbh1->prepare("select apples, bananas from fruit_salad");
$sth2=$dbh2->prepare("insert snack (apples, bananas) values (?,?)");
$sth1->execute(); 
while (@row=$sth1->fetchrow_array()) {
   $sth2->execute(@row);
}
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This way, you get the data out of your statement handle in a nice, simple array which you feed to your *other* statement handle.