Add partial support for INSERT IGNORE in MySQL mode

[katzyn]

Limitations:

1. Only duplicate key errors are ignored. MySQL also ignores other errors, but generates warnings for them. For duplicate key error there are no warnings in MySQL and in this implementation too.

2. I didn't test behaviour of MySQL when both IGNORE and ON DUPLICATE KEY UPDATE are specified. This implementation allows, but otherwise ignores IGNORE if ON DUPLICATE KEY UPDATE was also specified.

We have issue #455 for INSERT IGNORE, but this issue does not mention which parts of IGNORE are desired.

[katzyn]

I just checked latest MariaDB from its console. It doesn't count duplicate rows separately, but counts them as warnings. However, overall status and count of affected rows are still the same.

[fankaidev]

this is very helpful!

[ramsestom]

I tried to use the INSERT IGNORE statement with the latest version of H2 JDBC driver (1.4.197) but it do not seem to work.
For example if I do:
INSERT IGNORE INTO accounts (id, email) VALUES (1, 'test@yahoo.fr');
I have this error message:
Syntax error in SQL statement {0}; expected {1}; SQL statement
Whereas if I do a simple insert like
INSERT INTO accounts (id, email) VALUES (1, 'test@yahoo.fr');
everything works as expected (I have a duplicate key exeption if this record is already in the db else it is correctly inserted)

My accounts test table is defined like this:

CREATE TABLE IF NOT EXISTS accounts (
	id INTEGER PRIMARY KEY AUTO_INCREMENT,
	email VARCHAR NOT NULL,
	CONSTRAINT email_unique UNIQUE (email)
);

Any idea of what might cause this issue?

[katzyn]

INSERT IGNORE is not supported in Regular mode, you have to enable MySQL compatibility mode explicitly by appending ;MODE=MySQL to your database URL or by executing SET MODE MySQL statement.

Many messages in French localization were broken for a long time, this issue was fixed after 1.4.197 release. If you want to get correct error messages you need to build H2 from its current sources.

[ramsestom]

Thanks. using the ;MODE=MySQL flag fixed the problem