CREATE TABLE `test_index_1` (
  `id` bigint NOT NULL AUTO_INCREMENT COMMENT '主键',
  `a` int NOT NULL,
  `str1` varchar(255) DEFAULT NULL COMMENT 'str1',
  `str2` varchar(255) NOT NULL COMMENT 'str2',
  PRIMARY KEY (`id`),
  UNIQUE KEY `str2_key` (`str2`),
  KEY `a_key` (`a`),
  KEY `str1_key` (`str1`)
) ENGINE=InnoDB AUTO_INCREMENT=2 DEFAULT CHARSET=utf8mb4 COLLATE=utf8mb4_0900_ai_ci