( 6 months ago )
I have a MySQL table:
CREATE TABLE `content_html` (
`id` int(11) NOT NULL AUTO_INCREMENT,
`id_box_elements` int(11) DEFAULT NULL,
`id_router` int(11) DEFAULT NULL,
`content` mediumtext COLLATE utf8_czech_ci NOT NULL,
PRIMARY KEY (`id`),
UNIQUE KEY `id_box_elements` (`id_box_elements`,`id_router`)
and the UNIQUE KEY works just as expected, it allows multiple NULL rows of id_box_elements and id_router.
I am running MySQL 5.1.42, so probably there was some update on the issue discussed above. Fortunately it works and hopefully it will stay that way.