Is it possible to do something like that with data.table?
SELECT sum(a.abc)
FROM table_a as a
LEFT JOIN table_b as b
ON a.x = b.x AND (a.y=b.y or a.y=b.z or a.z=b.y or a.z=b.z)
Group by a.xyz
So my problem is to translate those or-conditions in the ON into
data.table syntax. I tried to do a cartesion join first and then
filter with the or-conditions and then do the groupby, which gives me
the desired results. But since I have large datasets (table_a and
table_b both have more than 1 million rows), I want to avoid the
cartesion join.
Any ideas how to do this in a more clever way?
Thanks,
Wolfgang
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