如何使用PHP检查MySQL中是否已经存在ip？

Question

This is my code, but it's not working; what's wrong?

$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

The ip is not a number, it is a text (or varchar). This is why you have to use:

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

Answer 2

我认为，如果您只需要计数，请使用COUNT（）

$sql = "SELECT COUNT(*) FROM ip WHERE ip = '".$_SERVER["REMOTE_ADDR"]."'";