double precision IS NULL does not work ?

15 Apr 2018

      Hello

I have those DOUBLE PRECISION fields, sometimes containing null values:

sql>select count(1), range_low from omop.measurement group by range_low;
+-----------+--------------------------+
| L2        | range_low                |
+===========+==========================+
| 304875924 |                     null |
|   9448250 |                       50 |
|  16519843 |                        0 |
|  13198932 |                       10 |
|  14364002 |                       20 |
|   3964808 |                       30 |
|   2998528 |                        3 |
|    855829 |                        2 |
+-----------+--------------------------+
8 tuples

However, I am not able to filter based on is null:

sql>select count(1) from omop.measurement where range_low is null;
+------+
| L3   |
+======+
|    0 |
+------+
1 tuple

I am not able to understand if this behavior is normal regarding the
documentation:

"The types REAL, FLOAT and DOUBLE map to the underlying implementation
system. No special attention is given to the value NaN."

Thanks

double precision IS NULL does not work ?

Nicolas Paris