Since you're on Cloudant (probably shouldn't post to the couchdb user list tbh);
index('purchase_date', purchase.time); // assuming purchase.time is an
epoch integer.
and use ?q=purchase_date:[earliest TO latest]&sort="purchase_date"
where earliest and latest are replaced by the appropriate number of
millis since epoch.
B.
On 11 March 2013 18:49, Traun Leyden <[email protected]> wrote:
> I want to be able to sort a list of users by how much they've spent in the
> last 6 months.
>
> The document has a structure of:
>
> {
> "type":"user",
> "purchases": [ {"type":"purchase","time":"2012-11-05
> 17:37:52","spent":50}, ...]
> }
>
> Here's how I'm planning on writing the index:
>
> var cutoffDate = new Date();
> cutoffDate.setHours(0,0,0,0);
> cutoffDate.setMonth(cutoffDate.getMonth() - 6);
> var total6m = 0;
> doc.purchases.forEach(function(purchase) {
> if((new Date(purchase.time)) > cutoffDate)) {
> spent6m += purchase.spent;
> }
> }
> index('spent6m', spent6m, {'store':'yes'});
>
> The disadvantage to this approach is that the indexed data quickly gets
> stale, because "new Date()" is only evaluated at index time and not when
> the query is run. Essentially it breaks the CouchDB rule of not having
> the view depend on external data.
>
> As a workaround, I'm thinking of adding a new field to the user object to
> store the purchase amount for the last 6 months, as well as adding a
> nightly process to update that field to keep the value from getting stale
> as time progresses.
>
> Is this the recommended approach or is there a cleaner way?
>
> Thanks,
> Traun
