Question

SQL语句 怎样按排序后显示前三个

$sql=mysql_query("select top 3 title from art_title join art_neirong on art_title.no=art_neirong.no order by last_update DESC;");

$i=0;
while($result=mysql_fetch_array($sql))
{
echo "<h5>".$result['title']."</h5>;
}

程序如上 为什么报错 该怎样改 谢谢
Warning: mysql_fetch_array(): supplied argument is not a valid MySQL result resource in
如果sql语句里没有top 3的话就可正常显示运行

Answer 1

没有看到你的数据库conn连接啊:
@$conn = mysql_connect("yourHost","yourUserID","yourPassword");

$sql=mysql_query("select top 3 title from art_title join art_neirong on art_title.no=art_neirong.no order by last_update DESC;",$conn);
//echo $sql;
$i=0;
while($result=mysql_fetch_array($sql))
{
echo "<h5>".$result['title']."</h5>;
}
mysql_close($conn);

追问

数据库在前面连过了 这样改还是不行。。

追答

我查了一下 貌似mysql数据库不支持top语法，你要是选取前三条数据 你可以把sql语句改成这么写，效果应该一样：
select title from art_title join art_neirong on art_title.no=art_neirong.no order by last_update DESC limit 3;

Answer 2

根据SQL 的语法规则，先执行Select 部分，然后才Order by，所以根据你的要求应该
Select top 3 (a.*) from (select *from tablename order by col1)a

Answer 3

select top 3 from table order by