3 ms·

> It’s a really compact syntax that deals with Cartesian product of lists. Couldn't taking the subset of a Cartesian product be considered to be dealing with o

• falcor84 9y ago
  Exactly. Indeed, from what I recall from relational database theory, joins are usually treated as cartesian products (outer joins) which are then filtered by the join condition.
  • catnaroek 9y ago
    An outer join a Cartesian product is not. Even if you stick to ordinary (inner) joins, they are pullbacks, not products. https://en.wikipedia.org/wiki/Pullback https://en.wikipedia.org/wiki/Pullback
    • falcor84 9y ago
      D'oh, sorry, I meant "cross join"