Hi,

I'm new to mongodb and trying to use it for reporting taking some data from
MySQL (e.g. fetch-and-modify as a purchase is made).  There are several
filters to the report such as product category id, gender, country,
affiliate, etc.  I'm thinking of two ways.  One is
{ _id : today,
  sale_amount : 100.00,
  gender : ,
  country : ,
...... }
for each purchase (without pre-aggregation).  Another one is
{ _id : { date : today, gender :    , country :    , (more filters) },
  sale_amount : 100.00,
  sale_count : 1 }

for each combination of filters (with pre-aggregation). An example of what
we need to see in the reporting is "Sales of product A per day made by male
in some country in the last 90 days."
If somebody can give me advice on how pre-aggregation should be done in
this example, I'd highly appreciate it.
Thank you in advance.

Fumiko