LeetCode--627. Salary exchange

DROP TABLE IF EXISTS `salary`;
CREATE TABLE `salary` (
  `id`int(11) NOT NULL,
  `name`varchar(10) NOT NULL,
  `sex`varchar(10) NOT NULL,
 `salary` int(11) NOT NULL,
  PRIMARYKEY (`id`)
) ENGINE=InnoDB DEFAULT CHARSET=utf8mb4;
-- ----------------------------
-- Records of salary
-- ----------------------------
INSERT INTO `salary` VALUES ('1', 'A', 'm','2500');
INSERT INTO `salary` VALUES ('2', 'B', 'f','1500');
INSERT INTO `salary` VALUES ('3', 'C', 'm','5500');
INSERT INTO `salary` VALUES ('4', 'D', 'f','500');

update salary set sex = if(sex = 'm', 'f','m');

UPDATE salary SET sex  = (CASE WHEN sex = 'm' THEN 'f' ELSE 'm' END)