title: Make unique index on json column
body: <p>How to make unique index on json type column in mysql? for example, I have translations column with slug property. I need unique slug among languages <a href="https://i.stack.imgur.com/RWKet.png" rel="nofollow noreferrer">translations column image</a></p>
  
  <p><code>
  CREATE TABLE `posts` (
    `id` int(10) unsigned NOT NULL AUTO_INCREMENT,
    `user_id` int(10) unsigned NOT NULL,
    `root_id` int(10) unsigned NOT NULL,
    `translations` longtext COLLATE utf8mb4_unicode_ci NOT NULL,
    `published_from` timestamp NOT NULL DEFAULT CURRENT_TIMESTAMP,
    `published_till` timestamp NOT NULL DEFAULT CURRENT_TIMESTAMP,
    `display_date` timestamp NOT NULL DEFAULT CURRENT_TIMESTAMP,
    `images` longtext COLLATE utf8mb4_unicode_ci,
    `deleted_at` timestamp NULL DEFAULT NULL,
    `created_at` timestamp NULL DEFAULT NULL,
    `updated_at` timestamp NULL DEFAULT NULL,
    PRIMARY KEY (`id`),
    KEY `posts_user_id_foreign` (`user_id`),
    KEY `posts_root_id_foreign` (`root_id`),
    CONSTRAINT `posts_root_id_foreign` FOREIGN KEY (`root_id`) REFERENCES `roots` (`id`) ON DELETE CASCADE ON UPDATE CASCADE,
    CONSTRAINT `posts_user_id_foreign` FOREIGN KEY (`user_id`) REFERENCES `admins` (`id`) ON UPDATE CASCADE
  ) ENGINE=InnoDB AUTO_INCREMENT=13 DEFAULT CHARSET=utf8mb4 COLLATE=utf8mb4_unicode_ci;
  </code></p>