Assuming you're using Cassandra 3.0 or more, User Defined Functions (UDF) can help you to compute the shipment_delay. For the ordering, since this column is computed and not a clustering column, ordering won't be possible
More details about UDF: http://www.doanduyhai.com/blog/?p=1876 On Mon, Oct 10, 2016 at 6:08 PM, Ali Akhtar <ali.rac...@gmail.com> wrote: > I have a table for tracking orders. Each order has an `ordered_at` field > (can be a timestamp, or a long with the milliseconds of the timestamp) and > `shipped_at` field (ditto, timestamp or long). > > orderd_at tracks when the order was made. > > shipped_at tracks when the order was shipped. > > When retrieving the orders, I need to calculate an additional field, > called 'shipment_delay'. This is simply, 'shipped_at - ordered_at`. I.e how > long it took between when the order was made, and when it was shipped. > > The tricky part is, that if an order isn't yet shipped, then it should > just return how many days it has been since the order was made. > > E.g, if order was made on Jan 1 and shipped on Jan 5th, shipment_delay = 4 > days (in milliseconds if needed) > > If order made on Jan 1, but not yet shipped, and today is Jan 10th, then > shipment_delay = 10 days. > > I then need to sort the orders in the order of 'shipment_delay desc', i.e > show the orders which took the longest, at the top. > > Is it possible to define 'shipment_delay' at the table or query level, so > it can be used in the 'order by' clause, or if this ordering will have to > be done myself after the data is received? > > Thanks. > >
