conditional aggregation
kan worden gebruikt
with Orders( BookId, Status ) as
(
select '123A','Perfect' union all
select '123B','Restore' union all
select '123C','Lost' union all
select '123D','Perfect' union all
select '123A','Perfect' union all
select '123B','Restore' union all
select '123A','Lost' union all
select '123B','Restore'
)
select
BookId,
sum(1) as [Total],
sum(case when Status='Perfect' then 1 else 0 end ) as [Perfect],
sum(case when Status='Restore' then 1 else 0 end ) as [Restore],
sum(case when Status='Lost' then 1 else 0 end ) as [Lost]
from
[Orders]
group by BookId;
BookId Total Perfect Restore Lost
123A 3 2 0 1
123B 3 0 3 0
123C 1 0 0 1
123D 1 1 0 0