-- 创建一般索引 CREATE TABLE tb_stu_info ( id INT NOT NULL, name CHAR(45) DEFAULT NULL, dept_id INT DEFAULT NULL, age INT DEFAULT NULL, height INT DEFAULT NULL, INDEX(height) ); -- 创建唯一索引 CREATE TABLE tb_stu_info2 ( id INT NOT NULL, name CHAR(45) DEFAULT NULL, dept_id INT DEFAULT NULL, age INT DEFAULT NULL, height INT DEFAULT NULL, UNIQUE INDEX(height) ); -- 查看索引 SHOW INDEX FROM tb_stu_info2; -- 删除索引 DROP INDEX height ON tb_stu_info;