Ignoring Errors
---------------

Normally INSERT stops and rolls back when it encounters an error.

By using the IGNORE keyword all errors are converted to warnings, which will
not stop inserts of additional rows.

Invalid values are changed to the closest valid value and inserted, with a
warning produced.

The IGNORE and DELAYED options are ignored when you use ON DUPLICATE KEY
UPDATE.

Prior to MySQL and MariaDB 5.5.28, no warnings were issued for duplicate key
errors when using IGNORE. You can get the old behavior if you set OLD_MODE to
NO_DUP_KEY_WARNINGS_WITH_IGNORE.

See IGNORE for a full description of effects.

Examples
--------

CREATE TABLE 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/