一、PHP/MySQL编程 2)同样上述内容管理系统:表comment记录用户回复内容,字段如下 文章id 文章标题 点击量 回复数量
用一个SQL语句完成上述查询,如果文章没有回复则回复数量显示为0 3) 上述内容管理系统,表category保存分类信息,字段如下 drop table if exists Comment; drop table if exists category; drop table if exists message; /*==============================================================*/ /* Table: Comment */ /*==============================================================*/ create table Comment ( comment_id int unsigned not null, id int unsigned not null, comment_content text, primary key (comment_id) ) type = InnoDB; /*==============================================================*/ /* Table: category */ /*==============================================================*/ create table category ( category_id int not null AUTO_INCREMENT, category_name varchar(40) not null, primary key (category_id), key AK_pk_category_id (category_id) ) type = InnoDB; /*==============================================================*/ /* Table: message */ /*==============================================================*/ create table message ( id int not null, title varchar(120) not null, content text not null, category_id int unsigned, hit int unsigned, primary key (id) ) type = InnoDB; select A.id,A.title,A.hits,IFNULL(B.num,0) from message A left join (select id,count(*) as num from comment B group by id) B on A.id=B.id order by B.num desc;
<html> <head><title>JS打印</title></head> <body> <form> <select id="category" name="category"> <?php mysql_connect("localhost","root","") or die("db conn error:".mysql_error()); mysql_select_db("phpinterview") or die("db error".mysql_error()); $result=mysql_query("select category_id,category_name from category"); while($row=mysql_fetch_array($result)) { echo "<option value='".$row["cateogry_id"]."'>".$row["category_name"]."</option>"; } ?> </select> </form> </body> |