mysql> create table t(id int unsigned);
Query OK, 0 rows affected (0.07 sec)

mysql> create table s(id int);
Query OK, 0 rows affected (0.05 sec)

mysql> insert into s values(-1);
Query OK, 1 row affected (0.01 sec)

mysql> insert into t select * from s;
ERROR 1690 (22003): constant -1 overflows int
mysql> import into t from select * from s;
ERROR 1690 (22003): constant -1 overflows int


mysql> set sql_mode='';
Query OK, 0 rows affected (0.00 sec)

mysql> insert into t select * from s;
Query OK, 1 row affected, 1 warning (0.03 sec)
Records: 1  Duplicates: 0  Warnings: 1

mysql> show warnings;
+---------+------+---------------------------+
| Level   | Code | Message                   |
+---------+------+---------------------------+
| Warning | 1690 | constant -1 overflows int |
+---------+------+---------------------------+
1 row in set (0.01 sec)

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

mysql> truncate table t;
Query OK, 0 rows affected (0.26 sec)

mysql> import into t from select * from s;
select * from t;
Query OK, 1 row affected (2.62 sec)
Records: 1, ID: 26a2f775-b3b4-4148-880c-523929a77573

mysql> select * from t;
+------------+
| id         |
+------------+
| 4294967295 |
+------------+
1 row in set (0.00 sec)