alter table tbl_name add col_name type
例如,給表增加一列weight
mysql>alter table pet add weight int
刪除列
alter table tbl_name drop col_name
例如，刪除列weight：
mysql>alter table pet drop weight
改變列
alter table tbl_name modify col_name type
例如，改變weight的類型：
mysql> alter table pet modify weight samllint
另一種方法是：
alter table tbl_name change old_col_name col_name type
例如：
mysql> alter table pet change weight weight samllint
給列更名
mysql>alter table pet change weight wei
給表更名
alter table tbl_name rename new_tbl
例如，把pet表更名為animal
mysql>alter table pet rename animal
Metric Converter is an useful tool for metric conversion, weight conversion, area conversion, mass conversion, angle conversion or any other unit conversions performed by, well, all. :)
