mysql adds modify field types and delete field types
- 2020-06-23 02:07:04
- OfStack
MySQL Add fields:
alter table `user_movement_log`
Add column GatewayId int not null default 0 AFTER `Regionid` ( After which field to add )
Delete fields:
alter table `user_movement_log` drop column Gatewayid
Adjust field order:
ALTER TABLE `user_movement_log` CHANGE `GatewayId` `GatewayId` int not null default 0 AFTER RegionID
// A primary key
alter table tabelname add new_field_id int(5) unsigned default 0 not null auto_increment ,add primary key (new_field_id);// increase 1 A new column
alter table t2 add d timestamp;
alter table infos add ex tinyint not null default '0';// Delete the column
alter table t2 drop column c;// Rename columns
alter table t1 change a b integer;
// Change the type of the column
alter table t1 change b b bigint not null;
alter table infos change list list tinyint not null default '0';
// Rename table
alter table t1 rename t2; indexed
mysql> alter table tablename change depno depno int(5) not null;
mysql> alter table tablename add index Index name ( The field name 1[ The field name 2 ... ]);
mysql> alter table tablename add index emp_name (name); Add the index of the primary keyword
mysql> alter table tablename add primary key(id); Add only 1 Index of restricted conditions
mysql> alter table tablename add unique emp_name2(cardnumber); Delete an index
mysql>alter table tablename drop index emp_name; Modify the table:
Add fields:
mysql> ALTER TABLE table_name ADD field_name field_type; Modify the original field name and type:
mysql> ALTER TABLE table_name CHANGE old_field_name new_field_name field_type; Delete fields:
mysql> ALTER TABLE table_name DROP field_name;