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From Justin Workman <>
Subject Re: First/last in npath
Date Wed, 21 Aug 2013 19:25:33 GMT
Assuming click stream type of data I want to get the search terms from the
first search request, and return the product id that was eventually viewed
and the number of clicks to the product. So something like this

select search_terms, productid, clicks_to_product from npath ( on clicks
                distributed by sessionid sort by timestamp
                arg2('SEARCH'), arg3(page = 'SEARCH'),
                arg4('PRODUCT'), arg5([age = 'PRODUCT'),
                arg6('first_value(search_terms) as search_terms,
last_value(productid) as productid, (size(tpath)-1) as clicks_to_product')

>From what I have seen, I will get the search terms from the first search
without the first_value, however it would be nice to be able to use
first_value to guarantee that. I cannot get the productid from the last
tpath object using this. I did try and get the last_value(tpath.productid)
in the outer query, however that returned the productid ( and all nulls
leading up to the product viewed page) in the very tpath value for the very
last row returned from the inner npath select, eg not the last value for
the productid for that row. I can use tpath.productid in place of productid
in the outer query and it returns the nulls for each row in the current
tpath, upto the final product view.

Hope this makes sense.


On Wed, Aug 21, 2013 at 12:42 PM, Harish Butani <>wrote:

> Can you provide details on what you want to do.
> You maybe able to express this by stacking queries: execute npath in a
> SubQuery in the from clause and then do windowing in an outer select.
> Also you get the 'path' object back from npath, so you can apply array
> indexing on it.
> regards,
> Harish.
> On Aug 20, 2013, at 10:43 PM, Justin Workman <>
> wrote:
> > When is it expect to support lead/lag/first_value/last_value in the
> > npath result statement?
> >
> > Thanks
> >
> >
> > Sent from my iPhone
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