"David G. Johnston" <david.g.johnston@gmail.com> writes:
> If the SRFs return a different number of rows the LCM behavior kicks in and
> you get Robert's second result.
Only if the periods of the SRFs are relatively prime. That is, neither of
his examples demonstrate the full weirdness of the current behavior; for
that, you need periods that are multiples of each other. For instance:
SELECT generate_series(1, 2), generate_series(1, 4); generate_series | generate_series
-----------------+----------------- 1 | 1 2 | 2 1 |
3 2 | 4
(4 rows)
That doesn't comport with any behavior available from LATERAL.
regards, tom lane
