DROP TABLE IF EXISTS bulletin;
CREATE TABLE bulletin(
 id INT NOT NULL PRIMARY KEY AUTO_INCREMENT, # 主键
 uid INT(11) NOT NULL DEFAULT 0, # 创建者id
 context VARCHAR(600) NOT NULL DEFAULT '', # 公告详细内容（300字）
 begintime DEC(20) NOT NULL DEFAULT 0, # 公告开始时间
 endtime DEC(20) NOT NULL DEFAULT 0, # 公告结束时间
 createtime DEC(20) NOT NULL DEFAULT 0, # 创建时间
 modifytime DEC(20) NOT NULL DEFAULT 0 # 修改时间
 PRIMARY KEY (`Id`),
)DEFAULT CHARSET=UTF8 TYPE=INNODB;

ALTER TABLE bulletin CHANGE uid username VARCHAR(50) NOT NULL DEFAULT '';

alter table bulletin add citycode varchar(6) not null default 0; # 城市代码

create database test character set utf8;

create table test(id int primary key)DEFAULT charset=utf8;

alter database test character set utf8;

alter table test character set utf8;

alter table test modify col_name varchar(50) CHARACTER SET utf8;

mysql>ALTER TABLE `table_name` ADD PRIMARY KEY ( `column` )

mysql>ALTER TABLE `table_name` ADD UNIQUE (
`column`
)

mysql>ALTER TABLE `table_name` ADD INDEX index_name ( `column` )

mysql>ALTER TABLE `table_name` ADD FULLTEXT (
`column`
)

mysql>ALTER TABLE `table_name` ADD INDEX index_name ( `column1`, `column2`, `column3` )