multiplication in if() clause

[admin]

i am having trouble with complex sort what i need to is check if the currency is not AUD, if not multiply it by the correct exchange rate to convert it to australian dollars and then do a sort on it. I am not sure what i am doing wrong, please help me.Select cruises.id as cruise_id, special_header as name, cruises.length as nights, currencies.name as currency, ships.name as ship, cruiselines.name as cruiseline, cruiselines.id as cl_id, destinations.name as destination, min(sailingdates.sailingdate) as sailingdate, exchangerates.currency_from as ex_rate, if('currency!=AUD', 'ex_rate*min(specialspricing.price)', 'min(specialspricing.price)') as pricefrom cruises left join currencies on cruises.currency_id = currencies.id left join ships on ships.id = cruises.ship_id left join cruiselines on cruiselines.id = cruises.cruiseline_id left join destinations on destinations.id = cruises.destination_id left join sailingdates on cruises.id = sailingdates.cruise_id left join specialspricing on cruises.id = specialspricing.cruise_id left join exchangerates on exchangerates.currency_from = currencies.name where on_special = 'y' AND sailingdates.special = 'y'AND sailingdates.sailingdate > now()and cruises.id = specialspricing.cruise_id