php - 如何使用 PHP 检查 ip 是否已存在于 MySQL 中？

Question

这是我的代码，但它不起作用；怎么了？

$ip = $_SERVER["REMOTE_ADDR"];
$con=mysqli_connect("DBHOST","DBUSER","DBPASS","DBNAME");
$check= 'SELECT * FROM ip WHERE ip = '.$_SERVER["REMOTE_ADDR"];
$rs = $con->query($check);
$data = mysqli_fetch_array($rs, MYSQLI_NUM);
$row_cnt = mysqli_num_rows($rs);
if( $row_cnt > 0 ) echo $row_cnt.' Records found';

Answer 1

ip 不是数字，而是文本(或 varchar)。这就是为什么你必须使用:

$check= "SELECT * FROM ip WHERE ip = '{$_SERVER["REMOTE_ADDR"]}'";