with t as(select '34052419800101001X'id from dual) select id from t where exists(select 1 from dual connect by level<=length(id)-1 --17 having mod(sum(substr(id,level,1)*power(2,18-level)),11)= case substr(id,-1,1) when '1' then 0 when '0' then 1 when 'X' then 2 else 12-substr(id,-1,1) end);