select yc,
       substr(yc, 0, instr(yc, '-') - 1),
       substr(yc, instr(yc, '-') + 1, length(yc)),
       t.*
  from tablename t
 where 1 = 1
 order by to_number(substr(yc, 0, instr(yc, '-') - 1)) asc;