This is how PostgreSQL currently works -
test=# select 'NaN'::float = 'NaN'::float as must_be_false; must_be_false
---------- t
(1 row)
I think that PostgreSQL's behaviour of comparing two
NaN-s as equal is wrong and Iwe should follow the IEEE 754 spec here
As per IEEE 754 a NaN behaves similar to NULL in SQL.
There is some discussion of why it is so at:
http://stackoverflow.com/questions/1565164/what-is-the-rationale-for-all-comparisons-returning-false-for-ieee754-nan-values
especially the first comment
---------
Hannu
