MySQL INSERT IGNORE Statement
Summary: in this tutorial, you will learn how to use the MySQL INSERT IGNORE
statement to insert data into a table.
Introduction to MySQL INSERT IGNORE
statement
When you use the INSERT
statement to add multiple rows to a table and if an error occurs during the processing, MySQL terminates the statement and returns an error. As the result, no rows are inserted into the table.
However, if you use the INSERT IGNORE
statement, the rows with invalid data that cause the error are ignored and the rows with valid data are inserted into the table.
The syntax of the INSERT IGNORE
statement is as follows:
INSERT IGNORE INTO table(column_list)
VALUES( value_list),
( value_list),
...
Code language: SQL (Structured Query Language) (sql)
Note that the IGNORE
clause is an extension of MySQL to the SQL standard.
MySQL INSERT IGNORE
example
We will create a new table called subscribers
for the demonstration.
CREATE TABLE subscribers (
id INT PRIMARY KEY AUTO_INCREMENT,
email VARCHAR(50) NOT NULL UNIQUE
);
Code language: SQL (Structured Query Language) (sql)
The UNIQUE
constraint ensures that no duplicate email exists in the email
column.
The following statement inserts a new row into the subscribers
table:
INSERT INTO subscribers(email)
VALUES('john.doe@gmail.com');
Code language: SQL (Structured Query Language) (sql)
It worked as expected.
Let’s execute another statement that inserts two rows into the subscribers
table:
INSERT INTO subscribers(email)
VALUES('john.doe@gmail.com'),
('jane.smith@ibm.com');
Code language: SQL (Structured Query Language) (sql)
It returns an error.
Error Code: 1062. Duplicate entry 'john.doe@gmail.com' for key 'email'
Code language: SQL (Structured Query Language) (sql)
As indicated in the error message, the email john.doe@gmail.com
violates the UNIQUE
constraint.
However, if you use the INSERT IGNORE
statement instead.
INSERT IGNORE INTO subscribers(email)
VALUES('john.doe@gmail.com'),
('jane.smith@ibm.com');
Code language: SQL (Structured Query Language) (sql)
MySQL returned a message indicating that one row was inserted and the other row was ignored.
1 row(s) affected, 1 warning(s): 1062 Duplicate entry 'john.doe@gmail.com' for key 'email' Records: 2 Duplicates: 1 Warnings: 1
Code language: SQL (Structured Query Language) (sql)
To find the detail of the warning, you can use the SHOW WARNINGS
command as shown below:
SHOW WARNINGS;
Code language: SQL (Structured Query Language) (sql)
In conclusion, when you use the INSERT IGNORE
statement, instead of issuing an error, MySQL issued a warning in case an error occurs.
If you query data from subscribers
table, you will find that only one row was actually inserted and the row that causes the error was not.
MySQL INSERT IGNORE
and STRICT
mode
When the strict mode is on, MySQL returns an error and aborts the INSERT
statement if you try to insert invalid values into a table.
However, if you use the INSERT IGNORE
statement, MySQL will issue a warning instead of an error. In addition, it will try to adjust the values to make them valid before adding the value to the table.
Consider the following example.
First, we create a new table named tokens
:
CREATE TABLE tokens (
s VARCHAR(6)
);
Code language: SQL (Structured Query Language) (sql)
In this table, the column s
accepts only string whose lengths are less than or equal to six.
Second, insert a string whose length is seven into the tokens
table.
INSERT INTO tokens VALUES('abcdefg');
Code language: SQL (Structured Query Language) (sql)
MySQL issued the following error because the strict mode is on.
Error Code: 1406. Data too long for column 's' at row 1
Code language: SQL (Structured Query Language) (sql)
Third, use the INSERT IGNORE
statement to insert the same string.
INSERT IGNORE INTO tokens VALUES('abcdefg');
Code language: SQL (Structured Query Language) (sql)
MySQL truncated data before inserting it into the tokens
table. In addition, it issues a warning.
In this tutorial, you have learned how to use the MySQL INSERT IGNORE
statement to insert rows into a table and ignore error for rows that cause errors.