Result of function BIT_OR is different from mysql.

[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 bit_or('-0.9871') ;

2. What did you expect to see?

mysql> select bit_or('-0.9871') ;
+-------------------+
| bit_or('-0.9871') |
+-------------------+
|                 0 |
+-------------------+
1 row in set, 1 warning (0.00 sec)

mysql> show warnings;
+---------+------+----------------------------------------------+
| Level   | Code | Message                                      |
+---------+------+----------------------------------------------+
| Warning | 1292 | Truncated incorrect INTEGER value: '-0.9871' |
+---------+------+----------------------------------------------+
1 row in set (0.00 sec)

3. What did you see instead?

mysql> select bit_or('-0.9871') ;
+----------------------+
| bit_or('-0.9871')    |
+----------------------+
| 18446744073709551615 |
+----------------------+
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

[ghost]

This has been fixed in master!

select bit_or('-0.9871') ;
SHOW WARNINGS;

..

mysql> select bit_or('-0.9871') ;
+-------------------+
| bit_or('-0.9871') |
+-------------------+
|                 0 |
+-------------------+
1 row in set, 1 warning (0.00 sec)

mysql> SHOW WARNINGS;
+---------+------+----------------------------------------------+
| Level   | Code | Message                                      |
+---------+------+----------------------------------------------+
| Warning | 1292 | Truncated incorrect INTEGER value: '-0.9871' |
+---------+------+----------------------------------------------+
1 row in set (0.00 sec)

mysql> SELECT tidb_version()\G
*************************** 1. row ***************************
tidb_version(): Release Version: v4.0.0-beta.2-762-g77aecd4b2
Edition: Community
Git Commit Hash: 77aecd4b27e79a97215eb4fdd68f68f2ddf67d21
Git Branch: master
UTC Build Time: 2020-07-13 01:43:31
GoVersion: go1.13
Race Enabled: false
TiKV Min Version: v3.0.0-60965b006877ca7234adaced7890d7b029ed1306
Check Table Before Drop: false
1 row in set (0.00 sec)

I am going to close this issue now.