未定义的GET ID? [英] undefined GET id?

问题描述

 <?php
$s = $_GET["s"];
if($s) {
$hent_b = mysql_query("SELECT * FROM member_battles WHERE state = '1' ORDER BY id DESC LIMIT 0,200") or die(mysql_error());
}else{
$hent_b = mysql_query("SELECT * FROM member_battles WHERE state = '0' ORDER BY id DESC LIMIT 0,200") or die(mysql_error());
}
while($vis = mysql_Fetch_array($hent_b)) {
 ?> 

我现在想要这个，当我进入我的网站(index.php)时，它应该不会出现未定义的$ _GET ["s"];

I have this now i want when i enter my site (index.php) it should not come up undefined $_GET["s"];

我该怎么做?但是我想要当您执行index.php?s时，它应该更改查询

how do i do this? but i want when you do index.php?s then it should change the query

推荐答案

使用 或 array_key_exists() :

if(isset($_GET['s'])) {

}

或

if(array_key_exists('s', $_GET)) {

}

这首先检查数组中是否确实存在一个键为s的元素.

This first checks if there really is an element in the array with a key s.

请勿在变量之前分配$_GET['s']，否则您将遇到同样的问题.

Don't assign $_GET['s'] to a variable before, otherwise you will have the same issue.

我个人总是会为参数分配一个值，即使用index.php?s=1而不是仅仅使用index.php?s.

I personally would always assign a value to a parameter, i.e. using index.php?s=1 instead of just index.php?s.

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