为什么mysqli不更新db记录，但它提供了一条成功的消息。当然，将显示以下消息：0条记录已成功更新，并且未对数据库进行任何更改。
我的索引php文件代码：

<?php

include 'connect.php';

$work = $_GET["work"];

if($work == "select"){

$query = "SELECT * FROM login ORDER BY City DESC";
$result = $connect->prepare($query);
$result ->execute();

$out = array();
while ($row = $result->fetch(PDO::FETCH_ASSOC)){
$record = array();
$record["InsID"] = $row["InsID"];

$record["Password"] = $row["Password"];

$record["Name"] = $row["Name"];

$record["City"] = $row["City"];

array_push($out,$record);

}

echo json_encode($out);

} elseif($work  == "update"){

$name2 = $_REQUEST["Ali"];

$code2 = $_REQUEST["4779"];

$city2 = $_REQUEST["teh"];

$pass2 = $_REQUEST["123"];

$query2 = "UPDATE login SET Password='$pass2',Name='$name2',City='$city2' WHERE InsID = '$code2'";

$result2 = $connect->prepare($query2);

$result2 ->execute();

}

?>

我真的不知道我的编码哪里错了。请帮忙。