mysql 索引 重名_mysql如何在设置主键时重命名主键索引

alter table tabelname add new_field_id int(5) unsigned default 0 not null auto_increment ,add primary key (new_field_id);

//增加一个新列alter table t2 add d timestamp;alter table infos add ex tinyint not null default '0';

//删除列alter table t2 drop column c;

//重命名列alter table t1 change a b integer;

//改变列的类型alter table t1 change b b bigint not null;alter table infos change list list tinyint not null default '0';

//重命名表alter table t1 rename t2;

//加索引mysql> alter table tablename change depno depno int(5) not null;mysql> alter table tablename add index 索引名 (字段名1[，字段名2 …]);mysql> alter table tablename add index emp_name (name);

//加主关键字的索引mysql> alter table tablename add primary key(id);

//加唯一限制条件的索引mysql> alter table tablename add unique emp_name2(cardnumber);

//删除某个索引mysql>alter table tablename drop index emp_name;