mysql 非严格模式插入一条为 null 的数据失败，插入多条就成功，有大佬指点下吗

mysql> status -------------- mysql Ver 14.14 Distrib 5.7.26, for Linux (x86_64) using EditLine wrapper Connection id: 29740 Current database: Current user: root@localhost SSL: Not in use Current pager: stdout Using outfile: '' Using delimiter: ; Server version: 5.7.26 MySQL Community Server (GPL) Protocol version: 10 Connection: Localhost via UNIX socket Server characterset: latin1 Db characterset: latin1 Client characterset: utf8 Conn. characterset: utf8 UNIX socket: /var/lib/mysql/mysql.sock Uptime: 6 days 23 hours 30 min 27 sec Threads: 1 Questions: 1984187 Slow queries: 0 Opens: 1555 Flush tables: 1 Open tables: 947 Queries per second avg: 3.290 -------------- mysql> SHOW VARIABLES LIKE "sql_mode"; +---------------+----------------------------------------------------------------------------------------------------+ | Variable_name | Value | +---------------+----------------------------------------------------------------------------------------------------+ | sql_mode | NO_ZERO_IN_DATE,NO_ZERO_DATE,ERROR_FOR_DIVISION_BY_ZERO,NO_AUTO_CREATE_USER,NO_ENGINE_SUBSTITUTION | +---------------+----------------------------------------------------------------------------------------------------+ 1 row in set (0.00 sec) mysql> desc test; +----------+------------------+------+-----+---------+----------------+ | Field | Type | Null | Key | Default | Extra | +----------+------------------+------+-----+---------+----------------+ | id | int(10) unsigned | NO | PRI | NULL | auto_increment | | name | varchar(255) | NO | | | | | add_time | int(11) | NO | | 0 | | +----------+------------------+------+-----+---------+----------------+ 3 rows in set (0.00 sec) mysql> INSERT INTO test (`name`, `add_time`) VALUES ('Albert', NULL); ERROR 1048 (23000): Column 'add_time' cannot be null mysql> INSERT INTO test (`name`, `add_time`) VALUES ('Albert', NULL),('Ben', NULL); Query OK, 2 rows affected, 1 warning (0.03 sec) Records: 2 Duplicates: 0 Warnings: 1 mysql> select * from test; +----+--------+----------+ | id | name | add_time | +----+--------+----------+ | 1 | Albert | 0 | | 2 | Ben | 0 | +----+--------+----------+ 2 rows in set (0.00 sec)