Yeah, the details are a little different, but I think the concept's similar. Is null < 0? Uh, not sure. Is it equal to zero? No clue. Is it greater than 0? Can't tell. So, are any of those true? No way of knowing.

  SQLite-3.54 in-memory-> select NULL < 0 or NULL == 0 or NULL > 0;
  ╭──────────────────────╮
  │ NULL < 0 or NULL ... │
  ╞══════════════════════╡
  │ NULL                 │
  ╰──────────────────────╯