cast as binary does not behave correctly when data is NaN

[birdstorm]

mysql> select /*+ READ_FROM_STORAGE(TIflash[t]) */ * from t where binary(c)='NaN';

+-------+
|   c   |
+-------+
|  NaN  |
+-------+
1 row in set (0.00 sec)

mysql> select /*+ READ_FROM_STORAGE(tikv[t]) */ * from t where binary(c)='NaN';
Empty set (0.01 sec)

v4.0.9

[leowangpingcap]

hi,
actually not just binary,
hex casting has the issue too, wondering if other types also can have this inconsistency behaviour:

mysql> select c, c = 0, hex(c), binary(c) from t;
+------+-------+------------------+----------------------+
| c | c = 0 | hex(c) | binary(c) |
+------+-------+------------------+----------------------+
| 0 | 0 | 8000000000000000 | 0x4E614E |
| 0 | 1 | 0 | 0x30 |
+------+-------+------------------+----------------------+
2 rows in set (0.01 sec)

able to reproduce in 5.1 and 5.2

[fuzhe1989]

@leowangpingcap could you tell me what values were inserted into table t? I can't tell the difference of the values of c in row1 and row2.