la tabella:

DROP TABLE IF EXISTS `user_match_profile`;
CREATE TABLE `user_match_profile` (
`ID_User` int(11) NOT NULL,
`ID_Std_Profile` int(11) NOT NULL,
`Percentage_Matching` int(11) NOT NULL,
PRIMARY KEY (`ID_User`,`ID_Std_Profile`),
KEY `ID_Std_Profile` (`ID_Std_Profile`)
) ENGINE=InnoDB DEFAULT CHARSET=utf8;

la vista:

select ID_User, ID_Std_Profile, Percentage_Matching
case
when Percentage_Matching < 20 then 'scarso'
when Percentage_Matching BETWEEN 20 and 60 then 'discreto'
else 'ottimo'
end
as descrizione
from user_match_profile

grazie mille