php向mysql写入数据失败

php向mysql写入数据失败，弄了好久都弄不出来。看看问题在哪
html：代码

html>
<html>
    <head>
        <meta charset="UTF-8">
        <link rel="stylesheet"  href="https://cdn.jsdelivr.net/npm/water.css@2/out/water.min.css"/>
        <title>title>
    head>
    <body>
        <form action="formData.php" method="get">
    <label>姓名:label><input type="text" name="user"/><br>
    <label>密码:label><input type="password" name="pass"><br>
    <input type="submit" value="注册"/>
form>
    body>
    
html>

php：代码：

$user=$_GET['user'];
$pass=$_GET['pass'];
$db_host="localhost";
$db_name="root";
$db_pwd="";
$link=mysqli_connect($db_host,$db_name,$db_pwd) ;//2.判断是否成功
if ($link){
echo"success";
}else {
echo"fail";}

//3.设置字符集
mysqli_set_charset($link,"utf8");
//4.选择数据库
mysqli_select_db($link,"lhy");
$sql = "use lhy;";
$sql += "INSERT into ifm(name,password) values ('$user','$pass');";
if ($link->query($sql) === TRUE) {
echo"新记录插入成功";
} else {
echo " Error:".$sql."
".$link->error;
}

数据库：

img


运行结果：

img

像他这样呢
https://blog.csdn.net/weixin_41735943/article/details/83963942