NaN Semantics
There is specially handling for not-a-number (NaN) when dealing with float or double types that
does not exactly match standard floating point semantics.
Specifically:
- NaN = NaN returns true.
- In aggregations, all NaN values are grouped together.
- NaN is treated as a normal value in join keys.
- NaN values go last when in ascending order, larger than any other numeric value.