Thanks for mentioning this other possibility! To be honest, I've discovered this possibility from you. Sadly, it doesn't improve the performance that much. We get the following performance:

- time: 98ms - throughput: 101Kelem/s

which is way slower than the 2.3ms and 4.18Melem/s we have with our final solution. It's even slower than the `CASE` without the `LEFT JOIN` (which was 39ms and 251Kelem/s).

Again, thanks for having pointed that out!