mysql 增加修改字段类型及删除字段类型

时间:2022-08-27 08:58:02

MySQL添加字段:

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alter table `user_movement_log`
 
Add column GatewayId int not null default 0 AFTER `Regionid` (在哪个字段后面添加)

删除字段:

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alter table `user_movement_log` drop column Gatewayid

调整字段顺序:

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ALTER TABLE `user_movement_log` CHANGE `GatewayId` `GatewayId` int not null default 0 AFTER RegionID
 
//主键
 
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;修改表:

增加字段:

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mysql> ALTER TABLE table_name ADD field_name field_type;修改原字段名称及类型:
 
mysql> ALTER TABLE table_name CHANGE old_field_name new_field_name field_type;删除字段:
 
mysql> ALTER TABLE table_name DROP field_name;