Frage an die SQL-Profis

[GerhardG]

Hallo,
so sollte es auch gehen:

with data (Key1, Key2, Key3, von, bis) as (values
(1, 1, 1, 10001, 10005),
(1, 1, 1, 10006, 10010),
(1, 1, 2, 10011, 10015),
(1, 1, 1, 10016, 10020),
(1, 1, 1, 10021, 10030),
(1, 1, 1, 10031, 10057)
),
     sort (Key1, Key2, Key3, von, bis, rn) as (
select key1, 
       key2, 
       key3, 
       von, 
       bis,
       row_number() over (order by key1,key2,key3)
from   data
),
     gruppen (crn, grp_Key1, grp_Key2, grp_Key3, grp_von, grp_bis, gruppe) as (
select rn, 
       key1, 
       key2, 
       key3, 
       von, 
       bis, 
       1
from   sort
where  rn = 1
union  all
select rn, 
       key1, 
       key2, 
       key3, 
       case when (key1, key2, key3) <> (grp_key1, grp_key2, grp_key3) then von 
            when von > grp_bis + 1 then von 
            else grp_von
       end,
       bis,
       case when (key1, key2, key3) <> (grp_key1, grp_key2, grp_key3) then gruppe + 1 
            when von > grp_bis + 1 then gruppe + 1
            else gruppe
       end
from   gruppen
inner  join sort on crn + 1 = rn
)

select grp_key1,
       grp_key2,
       grp_key3,
       min(grp_von),
       max(grp_bis)
from   gruppen
group  by grp_key1,grp_key2,grp_key3,gruppe
order  by min(grp_von)

1    1    1    10001    10010
1    1    2    10011    10015
1    1    1    10016    10057