E t1 (x INT UNIQUE);

INSERT INTO t1 VALUES(1),(2);

INSERT INTO t1 VALUES(2),(3);
ERROR 1062 (23000): Duplicate entry '2' for key 'x'
SELECT * FROM t1;
+------+
| x    |
+------+
|    1 |
|    2 |
+------+

INSERT IGNORE INTO t1 VALUES(2),(3);
Query OK, 1 row affected, 1 warning (0.04 sec)

SHOW WARNINGS;
+---------+------+---------------------------------+
| Level   | Code | Message                         |
+---------+------+---------------------------------+
| Warning | 1062 | Duplicate entry '2' for key 'x' |
+---------+------+---------------------------------+

SELECT * FROM t1;
+------+
| x    |
+------+
|    1 |
|    2 |
|    3 |
+------+

Converting values:

CREATE OR REPLACE TABLE t2(id INT, t VARCHAR(2) NOT NULL, n INT NOT NULL);

INSERT INTO t2(id) VALUES (1),(2);
ERROR 1364 (HY000): Field 't' doesn't have a default value

INSERT IGNORE INTO t2(id) VALUES (1),(2);
Query OK, 2 rows affected, 2 warnings (0.026 sec)
Records: 2  Duplicates: 0  Warnings: 2

SHOW WARNINGS;
+---------+------+----------------------------------------+
| Level   | Code | Message                                |
+---------+------+----------------------------------------+
| Warning | 1364 | Field 't' doesn't have a default value |
| Warning | 1364 | Field 'n' doesn't have a default value |
+---------+------+----------------------------------------+

SELECT * FROM t2;
+------+---+---+
| id   | t | n |
+------+---+---+
|    1 |   | 0 |
|    2 |   | 0 |
+------+---+---+

See INSERT ON DUPLICATE KEY UPDATE for further examples using that syntax.

URL: https://mariadb.com/kb/en/insert-ignore/https://mariadb.com/kb/en/insert-ignore/