回答

<?php

$pdo = new \PDO('mysql:host=localhost;dbname=guest;port=3306', 'guest', 'p6yhG8iDRMNxdJ9w');



// 第一种绑定方式

$param1 = "bfw";

$sql1 = "select * from User where username like ?";

$stmt1 = $pdo->prepare($sql1);

if ($stmt1->execute([

    "%$param1%",

])) {

    $res1 = $stmt1->fetchAll(\PDO::FETCH_ASSOC);

    print_r($res1);

}



//第二种绑定方法

$sql1 = 'SELECT *  FROM User WHERE username LIKE :username';





$stmt = $pdo->prepare($sql1);

$stmt->bindValue(':username','%'.$param1.'%');



$stmt->execute(); 

$rows = $stmt->fetchAll();

print_r($rows);



// IN 查询预处理

$param2 = [2,3,4];

$prepare = rtrim( str_pad('?', 2 * count($param2), ',?') , ',');

$sql2 = "select * from User where id  in($prepare)";

$stmt2 = $pdo->prepare($sql2);

if ($stmt2->execute($param2)) {

    $res2 = $stmt2->fetchAll(\PDO::FETCH_ASSOC);

    print_r($res2);

}