ROWNUM is actually more tricky than an extra attribute of the table, as it is influenced by ORDER BY. I guess I wouldn't prioritise support for ROWNUM, though.

ROWNUM is actually more tricky than an extra attribute of the table, as it is influenced by ORDER BY. I guess I wouldn't prioritise support for ROWNUM, though. There are more interesting, and more standard things. E.g. comparing a correlated subquery to a window function.