En het juiste antwoord is.
select Number, substr(
Site,
instr(','||Site,',',1,seq),
instr(','||Site||',',',',1,seq+1) - instr(','||Site,',',1,seq)-1) Site
from Sitetable,(select level seq from dual connect by level <= 100) seqgen
where instr(','||Site,',',1,seq) > 0