MySQL Add, delete fields, adjust fields

How should MySQL add fields be implemented? This is a lot of new contacts MySQL database has been mentioned, the following is to introduce you to MySQL add fields and delete the field method, I hope you can be enlightened.

MySQL add field:

ALTER TABLE ' User_movement_log ' add column Gatewayid int not null default 0 after ' RegionID ' (which field is added later)

To delete a field:

ALTER TABLE ' user_movement_log ' drop column Gatewayid

To adjust the order of fields:

alter table  ' User_movement_log '  CHANGE  ' Gatewayid '   ' 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 Column    alter table t2 drop  column c;//Renaming Columns    alter table t1 change a b integer;   //changing the type of column    alter table t1 change b b bigint not  null;  alter table infos change list list tinyint not  null default  ' 0 ';  //renaming tables    alter table t1 rename t2;//Gazzo citation    mysql>  alter table tablename change depno depno int (5)  not null;   mysql> alter table tablename add index  Index name   (field name 1[, field name 2  ...]);   mysql> alter table tablename add index emp_name  (name);// Index    mysql> alter table tablename add primary key (ID) of the main keyword;// Index    mysql> alter table tablename add unique emp_name2 with unique restriction conditions (cardnumber);//delete an index    mysql>alter table tablename drop index emp_ Name

Add Field:

MySQL Add, delete fields, adjust fields