變數引入方法

$sql="INSERT INTO users (name, sname, sex) VALUES  value (?,?,?,?)";
$stmt=$conn->prepare($sql);
$stmt->execute([$name,$sname,$sex]);

陣列方式

$data2=['s044','李金生',21,'女'];
$sql="INSERT INTO student(sno, sname, sage, ssex) VALUES (?,?,?,?) ";
$stmt=$conn->prepare($sql);
$stmt->execute($data2);

OR=============================

$data = [
    'name' => $name,
    'sname' => $sname,
    'sex' => $sex,
];
$sql = "INSERT INTO users (name, sname, sex) VALUES (:name, :sname, :sex)";
$stmt= $pdo->prepare($sql);
$stmt->execute($data);

OR ======================= 
$data = [
    'name' => $name,
    'sname' => $sname,
    'sex' => $sex,
];

$sql = "INSERT INTO users (name, sname, sex) VALUES (:name, :sname, :sex)";
$pdo->prepare($sql)->execute($data);

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https://phpdelusions.net/pdo_examples/update