Question

I have the following data:

 Date   ID Type Cost
 May 01   a  A    1
 May 01   b  A    2
 May 01   c  B    3
 May 01   d  B    4
 May 02   e  A    5
 May 02   f  A    6
 May 02   g  B    7
 May 02   h  B    8

I want a query that shows

Date       Type CostPercentage
May 01    A    (1+2) / (1+2+3+4)
May 01    B    (3+4) / (1+2+3+4)
May 02    A    (5+6) / (5+6+7+8)
May 02    B    (7+8) / (5+6+7+8)

What I currently have is

select Date, Type, sum(cost)
from mytable
group by Date, Type

I would really want to show the percentage, but that will involve deviding another number which is itself an aggregation.

How am I suppose to do that?

EDITED to reflect my real problem. I over simplified it before.

Answer 1

You could use a subquery:

select  dt.Date
,       dt.Type
,       SUM(dt.Cost) as DayTypeTotal
,       (select SUM(Cost) from @t d where d.Date = dt.Date) as DayTotal
,       100.0 * SUM(dt.Cost) / 
             (select SUM(Cost) from @t d where d.Date = dt.Date) as Percentage
from    @t dt
group by
        dt.Date
,       dt.Type

Link to working example @odata.