MySQL Change table structure: Add, delete, modify fields, adjust field order

To add a 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 ' 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 a column

ALTER TABLE T1 change b b bigint not null;
ALTER TABLE infos change list list tinyint not null default ' 0 ';

Renaming a table

ALTER TABLE t1 rename T2;

Add index

Mysql> ALTER TABLE tablename change depno depno int (5) is 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 of the plus primary keyword

Mysql> ALTER TABLE TableName ADD PRIMARY key (ID);

Index with unique restriction criteria

Mysql> ALTER TABLE tablename add unique emp_name2 (cardnumber);

Delete an index

Mysql>alter table tablename DROP index emp_name;

To modify a 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;

To delete a field:

mysql> ALTER TABLE table_name DROP field_name;

MySQL Change table structure: Add, delete, modify fields, adjust field order