и не могу разобраться в чем дело
CREATE TABLE `call_center_result` (
`id` int(11) unsigned NOT NULL AUTO_INCREMENT,
`operator_id` int(11) DEFAULT NULL,
`comment` int(11) DEFAULT NULL,
`id_task` int(11) DEFAULT NULL,
PRIMARY KEY (`id`),
KEY `id_task` (`id_task`)
) ENGINE=InnoDB DEFAULT CHARSET=utf8;
CREATE TABLE `call_center_task` (
`id_task` int(11) unsigned NOT NULL AUTO_INCREMENT,
`user_id` int(11) DEFAULT NULL,
`title` varchar(254) DEFAULT NULL,
`body` text,
`status` int(1) DEFAULT NULL,
`create` datetime DEFAULT NULL,
`start` datetime DEFAULT NULL,
`finish` datetime DEFAULT NULL,
`review` text,
PRIMARY KEY (`id_task`),
KEY `status` (`status`),
KEY `user_id` (`user_id`),
CONSTRAINT `call_center_task_ibfk_1` FOREIGN KEY (`user_id`) REFERENCES `users` (`id_user`) ON DELETE CASCADE
) ENGINE=InnoDB DEFAULT CHARSET=utf8;
И не могу выполнить команду
ALTER TABLE `call_center_result` ADD FOREIGN KEY (`id_task`) REFERENCES `call_center_task` (`id_task`) ON DELETE CASCADE ON UPDATE CASCADE;
выводит ошибку
#1215 - Cannot add foreign key constraint
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