尝试将数据从文本字段插入数据库时​​获取MySQL错误

Question

I am getting this error when trying to insert data into my database from my website:

Error: INSERT INTO newtask (new_category, new_department, new_required, 
new_name, new_address, new_contact, new_email,  new_logged, new_description) 
VALUES (?, ?, ?, ?, ?, ?, ?, ?, ?)
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

Here is my code:

<?php
$servername = 'localhost';
$username = 'root';
$password = '';
$dbname = 'tasks_db';


$conn = new mysqli($servername, $username, $password, $dbname);

if ($conn->connect_error) {
die("Connection failed: " . $conn->connect_error);
} 

$sql = "INSERT INTO newtask (new_category, new_department, new_required, 
new_name, new_address, new_contact, new_email,  new_logged, new_description) 
VALUES (?, ?, ?, ?, ?, ?, ?, ?, ?)";

if ($conn->query($sql) === TRUE) {
echo "New record created successfully";
} else {
echo "Error: " . $sql . "<br>" . $conn->error;
}

$conn->close();
?> 

Not sure what i am doing wrong here?

Answer 1

This is a prepared statement, so you need to prepare it, bind your values, and then execute it:

$stmt = $conn->prepare("INSERT INTO newtask (new_category, new_department, new_required, 
new_name, new_address, new_contact, new_email,  new_logged, new_description) 
VALUES (?, ?, ?, ?, ?, ?, ?, ?, ?)");

// One "s" per placeholder value, plus one value per "s" after
$stmt->bind_param("sssssssss", $new_category, $new_department, ...);

if ($stmt->execute()) {
  echo "New record created successfully";
} else {
  echo "Error: " . $sql . "<br>" . $conn->error;
}

Where $new_category is whatever value is going into that column and so on. This is all covered in the documentation.

The mistake is you were trying to run a SQL query with placeholder values and no data. ? is not a valid value in MySQL. It's replaced at the driver level by the bind_param operation on statements produced with prepare. The query function executes code as-is with no changes.