// 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 a column
alter table t2 drop column c;
// Rename a column
alter table t1 change a b integer;
// Change the column type
alter table t1 change b b bigint not null;
alter table infos change list list tinyint not null default '0';
// Rename the table
alter table t1 rename t2;
Add 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 );
Index with primary keywords
mysql> alter table tablename add primary key(id);
Add an index with unique conditions
mysql> alter table tablename add unique emp_name2(cardnumber);
Delete An index
mysql>alter table tablename drop index emp_name;
Modify 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;
Unique
Modify Table Name:
Alter table T1 rename T2