Form submitting duplicate comments to mysql table - php

Question

I have made a comment section to my pages which stores the comments in a mysql database. However when I click send, it sends duplicates of the same comment into the database. I can't see where I may have sent the query twice however.
<?php
if (!empty($_POST) && !empty($_POST['name']) && !empty($_POST['message'])) {
$name = strip_tags($_POST['name']);
$message = strip_tags($_POST['message']);
$name = mysqli_real_escape_string($db, $name);
$message = mysqli_real_escape_string($db, $message);
$query = "SELECT COUNT(*) AS count FROM comments";
$result = $db->query($query);
$data = $result->fetch_assoc();
$query = "INSERT INTO `comments` (`work_id`, `sender_ name`, `message`) VALUES ('".$id."','".$name."','".$message."')"; //id comes from a $_GET at the top of the page
$db->query($query);
$result = $db->query($query);
$query = "INSERT INTO `comment_work` (`comment_id`,`work_id`) SELECT `comments`.`id`, `comments`.`work_id` FROM `comments` WHERE `comments`.`sender_ name` = '".$name."' AND `comments`.`message` = '".$message."'";
$db->query($query);
$result = $db->query($query);
if ($result) {
echo "<p>Comment submitted!</p>";
} else {
echo "SQL Error: " . $db->error;
}
}
?>

Answer 1

Here
$query = "INSERT INTO `comments` (`work_id`, `sender_ name`, `message`) VALUES ('".$id."','".$name."','".$message."')"; //id comes from a $_GET at the top of the page
$db->query($query);//one query - **YOU must remove this line!**
$result = $db->query($query);//second query
To
$query = "INSERT INTO `comments` (`work_id`, `sender_ name`, `message`) VALUES ('".$id."','".$name."','".$message."')"; //id comes from a $_GET at the top of the page
$result = $db->query($query);
And here
$query = "INSERT INTO `comment_work` (`comment_id`,`work_id`) SELECT `comments`.`id`, `comments`.`work_id` FROM `comments` WHERE `comments`.`sender_ name` = '".$name."' AND `comments`.`message` = '".$message."'";
$result = $db->query($query);

Answer 2

Cause is simple:
Look at these code lines:
$query = "INSERT INTO `comments` (`work_id`, `sender_ name`, `message`) VALUES ('".$id."','".$name."','".$message."')"; //id comes from a $_GET at the top of the page
$db->query($query);
$result = $db->query($query);
$query = "INSERT INTO `comment_work` (`comment_id`,`work_id`) SELECT `comments`.`id`, `comments`.`work_id` FROM `comments` WHERE `comments`.`sender_ name` = '".$name."' AND `comments`.`message` = '".$message."'";
$db->query($query);
$result = $db->query($query);
Well, here you are executing a query with $db->query and then with $result = $db->query you executing another time the same query.
Replace this:
$query = "INSERT INTO `comment_work` (`comment_id`,`work_id`) SELECT `comments`.`id`, `comments`.`work_id` FROM `comments` WHERE `comments`.`sender_ name` = '".$name."' AND `comments`.`message` = '".$message."'";
$db->query($query);
$result = $db->query($query);
With:
$query = "INSERT INTO `comment_work` (`comment_id`,`work_id`) SELECT `comments`.`id`, `comments`.`work_id` FROM `comments` WHERE `comments`.`sender_ name` = '".$name."' AND `comments`.`message` = '".$message."'";
$result = $db->query($query);
And this:
$query = "INSERT INTO `comments` (`work_id`, `sender_ name`, `message`) VALUES ('".$id."','".$name."','".$message."')"; //id comes from a $_GET at the top of the page
$db->query($query);
$result = $db->query($query);
With:
$query = "INSERT INTO `comments` (`work_id`, `sender_ name`, `message`) VALUES ('".$id."','".$name."','".$message."')"; //id comes from a $_GET at the top of the page
$result = $db->query($query);
So should work.