mysql刪除主鍵索引，刪除索引語法
### Incorrect table definition; there can be only one auto column and it must be defined as a key
## 更新id列，去掉 AUTO_INCREMENT
ALTER TABLE mytest_config_back MODIFY COLUMN `id` INT(11) NOT NULL;
## 刪除主鍵索引 ALTER TABLE 表名 DROP INDEX 索引名稱;
ALTER TABLE mytest_config_back DROP INDEX `PRIMARY`;