zOs/SQL/EXWITH

with c (spc, c) as
(
  select bigInt(space)*1024, count(*)
    from sysibm.sysTableSpace
    group by space
)
select sum(c) "count", min(spc) "byte von", max(spc) "byte bis"
    from c
    group by case when spc <= 1 then spc -9
                  else floor(3 * log10(spc)) end
    order by 2 asc