On 28 October 2012 09:43, Hannu Krosing <ha...@2ndquadrant.com> wrote: > 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.
FWIW there is a note in the documentation about this: "Note: IEEE754 specifies that NaN should not compare equal to any other floating-point value (including NaN). In order to allow floating-point values to be sorted and used in tree-based indexes, PostgreSQL treats NaN values as equal, and greater than all non-NaN values." -- Sent via pgsql-hackers mailing list (pgsql-hackers@postgresql.org) To make changes to your subscription: http://www.postgresql.org/mailpref/pgsql-hackers
