Result of function OR is not correct.

[SunRunAway]

Bug Report

Please answer these questions before submitting your issue. Thanks!

1. What did you do?
   If possible, provide a recipe for reproducing the error.

SELECT 0 OR 0.00000001000000000000;
SELECT 0 OR 0.11234500000000000000;
SELECT NULL OR 0.00000001000000000000;

2. What did you expect to see?

mysql> SELECT 0 OR 0.00000001000000000000;
+-----------------------------+
| 0 OR 0.00000001000000000000 |
+-----------------------------+
|                           1 |
+-----------------------------+
1 row in set (0.00 sec)

mysql> SELECT 0 OR 0.11234500000000000000;
+-----------------------------+
| 0 OR 0.11234500000000000000 |
+-----------------------------+
|                           1 |
+-----------------------------+
1 row in set (0.00 sec)

mysql> SELECT NULL OR 0.00000001000000000000;
+--------------------------------+
| NULL OR 0.00000001000000000000 |
+--------------------------------+
|                              1 |
+--------------------------------+
1 row in set (0.00 sec)

3. What did you see instead?

mysql> SELECT 0 OR 0.00000001000000000000;
+-----------------------------+
| 0 OR 0.00000001000000000000 |
+-----------------------------+
|                           0 |
+-----------------------------+
1 row in set (0.00 sec)

mysql> SELECT 0 OR 0.11234500000000000000;
+-----------------------------+
| 0 OR 0.11234500000000000000 |
+-----------------------------+
|                           0 |
+-----------------------------+
1 row in set (0.00 sec)

mysql> SELECT NULL OR 0.00000001000000000000;
+--------------------------------+
| NULL OR 0.00000001000000000000 |
+--------------------------------+
|                           NULL |
+--------------------------------+
1 row in set (0.00 sec)

4. What version of TiDB are you using (tidb-server -V or run select tidb_version(); on TiDB)?

8c20289

[SunRunAway]

Fixed in #12173