Unnecessary warning on NULL computation.

[where2me]

Bug Report

Please answer these questions before submitting your issue. Thanks!

1. Minimal reproduce step (Required)

DROP TABLE IF EXISTS t0;
CREATE TABLE t0(c0 NUMERIC);
INSERT INTO t0 VALUES(1);
SELECT c0 FROM t0 WHERE NULL^(1 AND 'a');
SHOW WARNINGS;

2. What did you expect to see? (Required)

There should be no warning displayed, because NULL computes on ^ is always NULL.
Moreover, I want to know why the expression 'a' is treated as a DOUBLE value, not an INTEGER.

3. What did you see instead (Required)

mysql> SHOW WARNINGS;
+---------+------+---------------------------------------+
| Level | Code | Message |
+---------+------+---------------------------------------+
| Warning | 1292 | Truncated incorrect DOUBLE value: 'a' |
+---------+------+---------------------------------------+
1 row in set (0.00 sec)

4. What is your TiDB version? (Required)

mysql> SELECT tidb_version() ;
+----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------+
| tidb_version()

                               |

+----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------+
| Release Version: v5.3.0
Edition: Community
Git Commit Hash: 4a1b2e9
Git Branch: heads/refs/tags/v5.3.0
UTC Build Time: 2021-11-24 13:32:39
GoVersion: go1.16.4
Race Enabled: false
TiKV Min Version: v3.0.0-60965b006877ca7234adaced7890d7b029ed1306
Check Table Before Drop: false |
+----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------+
1 row in set (0.00 sec)