I have tried that
$UpdateQuery->bindColumn("SpecialOfferOldPrice", "s", "".((isset($_POST["SpecialOfferOldPrice"]))?str_replace(array("£","%",),"",($_POST["SpecialOfferOldPrice"])):"") ."", "WA_ZERO");
but that doesnt make that col 0 or blank. I guess the problem is that the column has a value in it from when the specialoffer was set , when you set the specialoffer to off, the SpecialOfferOldPrice still has a value in it and thats the value am trying to remove or zero