數據插入 - 捕獲的致命錯誤：類mysqli_result的對象不能被轉換成字符串

Question

下面是代碼

<?php 

require_once 'connection.php'; 

IF($_POST) 
{ 
$con = mysqli_connect($myServer, $myUser, $myPass); 

if (!$con) 
{ 
    die('Could not connect: ' . mysql_error()); 
} 

mysqli_select_db($con, $myDB) 
or die('Could not select DB'); 

$card_name = $_POST["Cname"]; 
$card_set = $_POST["Cset"]; 
$card_quantity = $_POST["Cquantity"]; 

$card_name = mysqli_real_escape_string($con, $card_name); 
$card_set = mysqli_real_escape_string($con, $card_set); 
$card_quantity = mysqli_real_escape_string($con, $card_quantity); 


$convert_name_query = "SELECT Nid FROM cards WHERE Nname = '".$card_name."'"; 
$convert_set_query = "SELECT Ncode FROM sets WHERE Nname = '".$card_set."'"; 

$convert_name = mysqli_query($con, $convert_name_query); 
$convert_set = mysqli_query($con, $convert_set_query); 

$query = "INSERT INTO inventory (Nid, Nset, Nqauntity) VALUES ($convert_name, $convert_set,  $card_quantity);"; 

IF (mysqli_query($con, $query)) { 
    echo "New cards added to inventory"; 
} else { 
echo "Error: " . $query . "</br>" . mysqli_error($con); 
} 

mysqli_close($con); 



} 

即時得到在線路這個錯誤37 捕獲的致命錯誤：類mysqli_result的對象無法轉換爲字符串addinv.php在線39

這是該行

$query = "INSERT INTO inventory (Nid, Nset, Nqauntity) VALUES ($convert_name, $convert_set, $card_quantity);"; 

我一直工作在這一段時間，我看不到米解決它。我問我的朋友太（沒有幫助，他知道ASP和PHP不

Answer 1

你必須用引號包裹查詢中的變量：

$query = "INSERT INTO inventory (Nid, Nset, Nqauntity) 
         VALUES ('$convert_name', '$convert_set', '$card_quantity')"; 

如果你想利用mysqli使用準備語句