Mysql adds and deletes the field type, mysql Field

Mysql adds and deletes the field type, mysql Field

Add a MySQL field:

Alter table 'user _ movement_log 'Add column GatewayId int not null default 0 AFTER 'regionid' (AFTER which field is added)

Delete field:

alter table `user_movement_log` drop column Gatewayid

Adjust the field order:

Alter table 'user _ movement_log 'CHANGE 'gatewayid' int not null default 0 AFTER RegionID // primary key alter table tabelname add new_field_id int (5) unsigned default 0 not null auto_increment, add primary key (new_field_id); // add a new column alter table t2 add d timestamp; alter table infos add ex tinyint not null default '0 '; // Delete the alter table t2 drop column c; // rename the alter table t1 change a B integer ;// Alter table t1 change B bigint not null; alter table infos change list tinyint not null default '0'; // rename alter table t1 rename t2; add the index mysql> alter table tablename change depno int (5) not null; mysql> alter table tablename add index name (field name 1 [, field name 2…]); Mysql> alter table tablename add index emp_name (name); add primary keyword index mysql> alter table tablename add primary key (id ); add the index mysql> alter table tablename add unique emp_name2 (cardnumber) with the unique restrictions; delete an index mysql> alter table tablename drop index emp_name; modify the table:

Add field:

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 field: mysql> alter table table_name DROP field_name;

How can I change the mysql field type?

Alter table chatter_users modify column ip VARCHAR (50 );

How can I change the type of a field in a table in Mysql?

First question
Alter table name
Alter column sex varchar (30)

Second question
Alter table name
Alter column sex as sexx