YEAR column is not compatible with MySQL

[cyliu0]

Bug Report

This PR #9856 fixed part of the issue. But we may need more fix.

Please answer these questions before submitting your issue. Thanks!

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

mysql> create table t (y year);
Query OK, 0 rows affected (0.01 sec)

mysql> insert ignore into t values(2156);
Query OK, 1 row affected, 1 warning (0.01 sec)

2. What did you expect to see?
   On MySQL:

mysql> select * from t;
+------+
| y    |
+------+
| 0000 |
+------+
1 row in set (0.00 sec)

3. What did you see instead?
   On TIDB:

mysql> select * from t;
+------+
| y    |
+------+
| 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)?

mysql> select tidb_version()\G
*************************** 1. row ***************************
tidb_version(): Release Version: v4.0.0-alpha-459-gebc122bb4
Git Commit Hash: ebc122bb48355149a8a18963f28e8d4e85e65551
Git Branch: master
UTC Build Time: 2019-10-11 03:10:45
GoVersion: go version go1.12.9 darwin/amd64
Race Enabled: false
TiKV Min Version: v3.0.0-60965b006877ca7234adaced7890d7b029ed1306
Check Table Before Drop: false
1 row in set (0.00 sec)

[lzmhhh123]

@cyliu0 Thank you for your report. Do you have any interest to fix it?

[cyliu0]

@cyliu0 Thank you for your report. Do you have any interest to fix it?

Sure. Let me have a try.