将数据插入 MySQL 数据库时出现错误吐回错误？

Question

我正在尝试使用 php 将数据插入 mysql 数据库。看起来很简单。

在使用虚拟数据（只是文本字符串）时，它工作得非常好。当我用实际变量替换虚拟数据时，我得到了这个错误：

ERROR: Could not able to execute INSERT INTO tbl_users (id, timestamp, testid, email, wants_newsletter, ip, country) VALUES (NULL, CURRENT_TIMESTAMP, , , , , ). You have an error in your SQL syntax; check the manual that corresponds to your MySQL server version for the right syntax to use near ' , , , )' at line 1

下面是我正在使用的脚本。我 100% 确定所有变量都有效。我目前也让他们吐出虚拟数据。

$testid = 1;
$email = 'test@yahoo.com'
$wants_newsletter = true;
//get $ip
if (!empty($_SERVER['HTTP_CLIENT_IP'])) {
    $ip = $_SERVER['HTTP_CLIENT_IP'];
} elseif (!empty($_SERVER['HTTP_X_FORWARDED_FOR'])) {
    $ip = $_SERVER['HTTP_X_FORWARDED_FOR'];
} else {
    $ip = $_SERVER['REMOTE_ADDR'];
}
$country = 'US';

$user_id = 100; 
$question = 14
$answer = 14    

function saveToDB() {

/* Attempt MySQL server connection. */
$link = mysqli_connect("localhost", "$user", "$pass", "$db");

// Check connection
if($link === false){
    die("ERROR: Could not connect. " . mysqli_connect_error());
}

// Attempt insert query execution
$sql = "INSERT INTO tbl_users (id, timestamp, testid, email, wants_newsletter, ip, country) VALUES (NULL, CURRENT_TIMESTAMP, $testid, $useremail, $newsletter, $ip, $country)";

if(mysqli_query($link, $sql)){
    echo "Records inserted successfully.";
    $user_id = $link->insert_id;
} else{
    echo "ERROR: Could not able to execute $sql. " . mysqli_error($link);
}

// Attempt insert query execution
$sql = "INSERT INTO tbl_answers (id, user_id, question_id, answer) VALUES (NULL, $user_id, $question, $answer)";

if(mysqli_query($link, $sql)){
    echo "Records inserted successfully.";
} else{
    echo "ERROR: Could not able to execute $sql. " . mysqli_error($link);
}

// Close connection
mysqli_close($link);


}//end saveToDB

saveToDB(); //Call saveToDB()

为了找出这个错误，我已经绞尽脑汁好几个小时了。它可能是我忽略的小东西，也许我需要一双新的眼睛。

任何帮助将不胜感激。

Answer 1

根据您收到的 SQL 错误，您传递给内插字符串的变量似乎没有设置。

在插入语句之前检查$testid、$useremail、$newsletter、$ip 和$country 的值。

在任何情况下，正如其他人所建议的那样，无论哪种方式，您都希望使用准备好的语句。查看PDO objects。