Tricky GROUP BY-udgave på ORACLE

I Oracle 11 kan du bruge pivot klausul sammen med unpivot klausul:

with 
count_table as (
     select 1001 device_id,  4 quantity from dual union all
     select 1002 device_id, 20 quantity from dual union all
     select 1003 device_id,  1 quantity from dual 
),
device_table as (
     select 1001 id, 'Yes'     wifi, 'No'       email, 'No'  bluetooth from dual union all
     select 1002 id, 'Yes'     wifi, 'Yes'      email, 'No'  bluetooth from dual union all
     select 1003 id, 'Unknown' wifi, 'Unknown'  email, 'Yes' bluetooth from dual 
)
----------------------------------------
select * from (
      select
        feature,
        yes_no_unknown,
        sum(quantity)  quantity
      from 
         count_table  c join 
         device_table d on c.device_id = d.id
      unpivot  ( yes_no_unknown
                 for feature in (wifi, email, bluetooth)
      ) 
      group by 
      feature,
      yes_no_unknown
)  
pivot ( sum (quantity)
        for yes_no_unknown in ('Yes' as yes, 'No' as no, 'Unknown' as unknown)
)
;

Alternativt vil du måske forbinde de to eksisterende tabeller til en tredje tabel, der indeholder værdierne for de tre ønskede rækker. Det er nok også lidt nemmere at læse:

with 
count_table as (
     select 1001 device_id,  4 quantity from dual union all
     select 1002 device_id, 20 quantity from dual union all
     select 1003 device_id,  1 quantity from dual 
),
device_table as (
     select 1001 id, 'Yes'     wifi, 'No'       email, 'No'  bluetooth from dual union all
     select 1002 id, 'Yes'     wifi, 'Yes'      email, 'No'  bluetooth from dual union all
     select 1003 id, 'Unknown' wifi, 'Unknown'  email, 'Yes' bluetooth from dual 
)
----------------------------------------
select
   f.txt,
   sum(case when ( f.txt = 'wifi'      and d.wifi      = 'Yes' ) or
                 ( f.txt = 'email'     and d.email     = 'Yes' ) or
                 ( f.txt = 'bluetooth' and d.bluetooth = 'Yes' ) 
            then   c.quantity
            else   0 end
      ) yes,
   sum(case when ( f.txt = 'wifi'      and d.wifi      = 'No' ) or
                 ( f.txt = 'email'     and d.email     = 'No' ) or
                 ( f.txt = 'bluetooth' and d.bluetooth = 'No' ) 
            then   c.quantity
            else   0 end
      ) no,
   sum(case when ( f.txt = 'wifi'      and d.wifi      = 'Unknown' ) or
                 ( f.txt = 'email'     and d.email     = 'Unknown' ) or
                 ( f.txt = 'bluetooth' and d.bluetooth = 'Unknown' ) 
            then   c.quantity
            else   0 end
      ) unknown
from 
   count_table  c                                   join 
   device_table d on c.device_id = d.id     cross   join
   (
        select 'wifi'      txt from dual union all
        select 'email'     txt from dual union all
        select 'bluetooth' txt from dual
   ) f
group by 
    f.txt;