使用 insert ignore 插入数据时，若遇主键、唯一索引冲突，则不会插入数据，且不会报错。
示例1
create table `user_info` (
`id` bigint unsigned not null auto_increment comment '自增ID',
`name` varchar(45) not null default '' comment '用户名',
primary key (`id`)
) engine = InnoDB character set = utf8mb4;
mysql> insert into user_info (id, name) values(1, 'letian');
Query OK, 1 row affected
mysql> insert into user_info (id, name) values(1, 'letian2');
(1062, u"Duplicate entry '1' for key 'PRIMARY'")
mysql > select * from user_info;
+----+--------+
| id | name |
+----+--------+
| 1 | letian |
+----+--------+
mysql> insert ignore into user_info (id, name) values(1, 'letian2');
Query OK, 0 rows affected
mysql> select * from user_info;
+----+--------+
| id | name |
+----+--------+
| 1 | letian |
+----+--------+
mysql> insert ignore into user_info (id, name) values(2, 'letian2');
Query OK, 1 row affected
mysql> select * from user_info;
+----+---------+
| id | name |
+----+---------+
| 1 | letian |
| 2 | letian2 |
+----+---------+
示例2
create table `user_info` (
`id` bigint unsigned not null auto_increment comment '自增ID',
`name` varchar(45) not null default '' comment '用户名',
`note` varchar(1024) not null default '' comment '备注',
primary key (`id`),
unique key idx_name(name)
) engine = InnoDB character set = utf8mb4;
mysql> insert into user_info (name) values('letian');
mysql> insert into user_info (name) values('letian');
Query OK, 1 row affected
mysql> select * from user_info;
+----+--------+------+
| id | name | note |
+----+--------+------+
| 1 | letian | |
+----+--------+------+
mysql> insert into user_info (name, note) values('letian', '备注');
(1062, u"Duplicate entry 'letian' for key 'idx_name'")
mysql> insert ignore into user_info (name, note) values('letian', '备注');
Query OK, 0 rows affected