tidb allows NULL value to NOT NULL column

[mzhang77]

Bug Report

Please answer these questions before submitting your issue. Thanks!

1. Minimal reproduce step (Required)

mysql> select @@sql_mode;
+------------+
| @@sql_mode |
+------------+
|            |
+------------+
1 row in set (0.00 sec)

mysql> create table t( pk int primary key not null auto_increment, data binary(12) not null);
Query OK, 0 rows affected (0.06 sec)

mysql> insert into t(data) values (null);
Query OK, 1 row affected, 1 warning (0.00 sec)

mysql> select * from t;
+----+----------------------------+
| pk | data                       |
+----+----------------------------+
|  1 | 0x000000000000000000000000 |
+----+----------------------------+
1 row in set (0.00 sec)

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

Tidb should not allow insert of NULL value to NOT NULL column. See below mysql result:

mysql> select @@sql_mode;
+------------+
| @@sql_mode |
+------------+
|            |
+------------+
1 row in set (0.00 sec)

mysql> create table t( pk int primary key not null auto_increment, data binary(12) not null);
Query OK, 0 rows affected (0.01 sec)

mysql> insert into t(data) values (null);
ERROR 1048 (23000): Column 'data' cannot be null
mysql> select @@version;
+-----------+
| @@version |
+-----------+
| 8.0.40    |
+-----------+
1 row in set (0.00 sec)

3. What did you see instead (Required)

tidb allows insert of NULL value to NOT NULL column, it's incompatible with mysql

4. What is your TiDB version? (Required)

mysql> select @@version;
+--------------------+
| @@version          |
+--------------------+
| 8.0.11-TiDB-v7.5.3 |
+--------------------+
1 row in set (0.00 sec)