| -- The non-obvious property: selectivity changes across the scan. Rows arrive in | |
| -- `seq` order; `a_sel = 0` matches ~0.1% in the first 10% of rows and ~50% | |
| -- after, `b_sel = 0` is the mirror -- so which predicate is more selective flips | |
| -- partway through. cf. q81 (opposite order). | |
| SELECT count(*) FROM t | |
| WHERE a_sel = 0 | |
| AND b_sel = 0; |