修改表结构的MYSQL

alter table tb_zhongjiang add index idx_userid(userid);

alter table tabelname add columnname varchar2(8) NULL;
alter table frontweb_blacklist
删除主键索引
ALTER TABLE `ubs_front_webpage`.`frontweb_blacklist1` DROP PRIMARY KEY;
创建自增id主键
alter table frontweb_blacklist1 add id int(10) NOT NULL auto_increment primary key;
创建唯一键索引
ALTER TABLE `ubs_front_webpage`.`frontweb_blacklist1` ADD UNIQUE INDEX `Index_unique_keyword`(`keyword`); 1 add id int(10) NOT NULL auto_increment