php - 如何将mysqli_query结果转换为int？

目前我正在开发一个移动图书馆应用程序，它将需要检查书籍。我想能够检查出有多少书，相比之下，总的可用。我正在努力将mysqli_query结果转换成一个整数，以与可用的图书总量进行比较。我很抱歉，如果这是一个简单的答案（我很新），因为我做了相当多的挖掘，无法找到一个答案，我可以适应我的情况。

<?php
require "conn.php";

$userID = "2";
$book_id = "1";

$mysql_qry = "select COUNT(*) from books_checked_out where bookID=$book_id";
$result = mysqli_query($conn, $mysql_qry);

//Somewhere here convert the $result into $quantity, which would be an int

if($quantity >= 2) {
    echo "more books checked out than in stock";
}
else if($quantity < 2) {
    echo "less books checked out than in stock";
}
?>

感谢您的帮助！

最佳答案

你可以这样做：

$userID = "2";
$book_id = "1";

$mysql_qry = "select COUNT(*) as quantity from books_checked_out where bookID=$book_id";
$result = mysqli_query($conn, $mysql_qry);

$row = mysqli_fetch_array($result, 'MYSQLI_ASSOC'); // Use something like this to get the result
$quantity = $row['quantity'];

if($quantity >= 2) {
    echo "more books checked out than in stock";
}
else if($quantity < 2) {
    echo "less books checked out than in stock";
}
?>