//主键 ALTER TABLE tablename add new_field_id int(5) UNSIGNED DEFAULT 0 NOT NULL anto_increment,ADD PRIMARY KEY (new_field_id); //增加一个新列 mysqlALTER TABLE tablename ADD fieldname fieldtype 如： ALTER TABLE t2 ADD d TIMESTAMP;
//主键 ALTER TABLE tablename add new_field_id int(5) UNSIGNED DEFAULT 0 NOT NULL anto_increment,ADD PRIMARY KEY (new_field_id); //增加一个新列 mysql>ALTER TABLE tablename ADD fieldname fieldtype 如： ALTER TABLE t2 ADD d TIMESTAMP; ALTER TABLE infos ADD ex TINYINT NOT NULL DEFAULT '0'; //删除列 mysql>ALTER TABLE table_name DROP field_name 如： ALTER TABLE t2 DROP COLUMN c; //修改原字段名称及类型 mysql>ALTER TABLE tablename CHANGE old_field_name new_field_name field_type; 如： //重命名列 ALTER TABLE t1 CHANGE a b INTEGER; //改变列的类型 ALTER TABLE t1 CHANGE b b BIGINT NOT NULL; ALTER TABLE infos CHANGE list list TINYINT NOT NULL DEFAULT '0'; //重命名表 ALTER TABLE t1 RENAME t2; //加索引 mysql>ALTER TABLE tablename CHANGE depno depno int(5) NOT NULL; mysql>ALTER TABLE tablename ADD INDEX 索引名 (字段名1[,字段名2……]); mysql>ALTER TABLE tablename ADD INDEX emp_name(name); //加主关键字的搜索 mysql>ALTER TABLE tablename ADD PRIMARY KEY(id); //加唯一限制条件的索引 mysql>ALTER TABLE tablename ADD UNIQUE emp_name2(cardnumber); //删除某个索引 mysql>ALTER TABLE tablename DROP INDEX emp_name;
