Weird behaviour when joining

[iagogv3]

Reading the new join vignettes I found

data.table/vignettes/datatable-joins.Rmd

Lines 557 to 562 in 4f7f567

	- The date related `ProductReceivedProd2` was omitted from this new table.
	```{r}
	ProductReceivedProd2[ProductSalesProd2,
	on = list(product_id, date < date)]
	```

which I did not understood initially the full consequences of this, but later, working with my own data, I realised it means losing data from x (if doing x[y, on = .(xid = yid, date < ydate),...]).

I may use something like x[y, on = .(xid = yid), j = .(date = x.date), ...], but then I have to specify inside j = .(...) all the columns from x and y (which may be a lot). I have tried including .SD, x.SD, x..SD, i.SD, i..SD in distinct ways, but nothing of this works.

Is there an abbreviated way to include all x and y (i) columns in the join, while using j to specify some names or some concrete data columns?

[tdhock]

related to #4949

[tdhock]

probably fixed by #3093 (please look at that PR, it needs help)

[iagogv3]

@tdhock Thanks for pointing me to the original issue and to the PR (I looked at it, but it is too much complex for the time I have now)

[tdhock]

me too