MySQL drop index語句

• Drop index語句用來刪除索引操作

mysql> drop index idx_125 on students;
Query OK, 0 rows affected (0.07 sec)
Records: 0  Duplicates: 0  Warnings: 0

mysql> show create table students;
+----------+--------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------+
| Table    | Create Table                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                 |
+----------+--------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------+
| students | CREATE TABLE `students` (
  `sid` int(11) NOT NULL AUTO_INCREMENT,
  `sname` varchar(64) DEFAULT NULL,
  `gender` varchar(12) DEFAULT NULL,
  `dept_id` int(11) NOT NULL,
  PRIMARY KEY (`sid`),
  UNIQUE KEY `idx_1` (`sname`),
  KEY `for_1` (`dept_id`),
  KEY `idx_123` (`sid`,`sname`),
  KEY `idx_124` (`sid`),
  KEY `idx_126` (`sname`),
  CONSTRAINT `for_1` FOREIGN KEY (`dept_id`) REFERENCES `dept` (`id`)
) ENGINE=InnoDB AUTO_INCREMENT=102 DEFAULT CHARSET=utf8mb4 COLLATE=utf8mb4_0900_ai_ci |
+----------+--------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------+
1 row in set (0.00 sec)