err:SELECT id,img,num_ordine,nome,cognome,descr,descr_en,descr_breve,commento_en,descr_breve_en,commento,link1,link2,link3,commento_img,online,link4,anno FROM tbldiplomati WHERE online=1 and id in (select iddiplomati from tblstudenti_corsi sc inner join tblcorsi c on c.id=sc.idcorso where c.idstrumento = (select id from tblstrumenti where codice='violino-pop-rock')) order by cognome,nome <br>