php query whether the user exists
First get the user name through $_GET["username"]; then use mysqli connects to the database and uses query to query the database; if the query result is greater than 0, the user exists, otherwise the user does not exist.
<?php header("Content-Type:text/html;charset=utf8"); $username = $_GET["username"]; //获取输入用户名 // $password = $_GET["password"]; //获取输入密码 $mysql_server_name = "localhost:3306"; //连接数据库端口 $mysql_username = "root"; //用户名 $mysql_password = "123456"; //密码 $mysql_database = "test"; //数据库名称 $conn = new mysqli($mysql_server_name, $mysql_username, $mysql_password, $mysql_database); //构造函数mysql // $sql = $conn->query("select username from user where username ='{$username}' and password = '{$password}'"); //查询数据库中的用户名和密码 并返回集合 $sql = $conn->query("select username from user where username ='{$username}'"); $row = mysqli_fetch_assoc($sql); //取其中一行 if ($row > 0) { //判断是否存在 echo "{$username}用户存在"; } else { echo "{$username}用户不存在"; } ?>
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