Very simplistics - select M fields, filters on N fields, slight bias to
use values of same type of the field it's comparing against.
No segfaults yet, but one test case that generates differing output when
run against `nulls` and `nulls1`:
```
select rowid from nulls1 where binary_9 >= '56' and ts_5 < 496886400000;
```
893e4c63f5