unexpected error message in php form (SQL syntax error) - php

Question

I have made a simple php cms form with database but it does not work properly when I want to submit the form with some dummy data! I don't know why it happens & also I added the mysqli_error() to get the type of error that I'm facing with but I only got this:
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 2
<?php
if (isset($_POST['submit'])){
$post_title = $_POST['title'];
$post_date = date('d-m-y');
$post_author = $_POST['author'];
$post_keywords = $_POST['keywords'];
$post_content = $_POST['content'];
$post_image = $_FILES['image']['name'];
$image_tmp = $_FILES['image']['tmp_name'];
if ($post_title=='' or $post_keywords='' or $post_content='' or $post_author=''){
echo '<script>alert("Some fields are missing")</script>';
}else{
move_uploaded_file($image_tmp,"post_images/$post_image");
$insert_query = "INSERT INTO posts
(post_title,post_date,post_author,post_image,post_keywords,post_content) VALUES ('$post_title','$post_date','$post_author',$post_image','$post_keywords','$post_content')";
$insert_post = mysqli_query($con,$insert_query);
if ($insert_post){
echo '<h3 style="color:green">Post has been added successfully.</h3>';
}else{
echo mysqli_error($con);
}
}
}
?>
<form method="POST" action="" enctype="multipart/form-data">
<table width="600" align="center" border="10">
<tr>
<td align="center"><h6>Insert Post Title</h6></td>
<td align="center"><input type="text" name="title"/></td></br>
</tr>
<tr>
<td align="center"><h6>Insert Post Author</h6></td>
<td align="center"><input type="text" name="author"/></td></br>
</tr>
<tr>
<td align="center"><h6>Insert Post Keywords</h6></td>
<td align="center"><input type="text" name="keywords"/></td></br>
</tr>
<tr>
<td align="center"><h6>Insert Post Image</h6></td>
<td align="center"><input type="file" name="image"/></td></br>
</tr>
<tr>
<td align="center"><h6>Insert Post Content</h6></td>
<td align="center"><textarea name="content" cols="10" rows="10"></textarea></td></br>
</tr>
<tr>
<td align="center"><input type="submit" name="submit" value="Submit"/></td>
</tr>
</table>
</form>
It would be very helpful to me if you share your solution for this problem... thanks!

Answer 1

You are missing a quote just before $post_image:
,$post_image'
Should be:
,'$post_image'
So the complete SQL statement becomes then:
$insert_query = "INSERT INTO posts
(post_title, post_date, post_author, post_image, post_keywords, post_content)
VALUES ('$post_title', '$post_date', '$post_author', '$post_image',
'$post_keywords', '$post_content')";
Please note that you are doing assignments in this if:
if ($post_title=='' or $post_keywords='' or $post_content='' or $post_author=''){
You should be using double == instead of =.
Finally, your code is vulnerable to SQL injection. So please use prepared statements with parameters.

Answer 2

writing if statement in this way is better
// this not always works
if ($post_title=='' or $post_keywords='' or $post_content='' or $post_author=''){
echo '<script>alert("Some fields are missing")</script>';
}
// yeah much better
if (empty($post_title) || empty($post_keywords) || empty($post_content) || empty($post_author)){
echo '<script>alert("Some fields are missing")</script>';
}
and sql mistake most probably because of here
'$post_keywords','$post_content')";
$post_keywords and $post_content is null or empty

Answer 3

Changes
Use empty for check empty variable
Use || instead of or
Check validation for what you are doing. (move_uploaded_file)
Be careful with quotes ($post_image') - This is the bug in your code
Enhance mysqli_error (if (!$insert_post){)
Code
<?php
if (isset($_POST['submit']))
{
$post_title = $_POST['title'];
$post_date = date('d-m-y');
$post_author = $_POST['author'];
$post_keywords = $_POST['keywords'];
$post_content = $_POST['content'];
$post_image = $_FILES['image']['name'];
$image_tmp = $_FILES['image']['tmp_name'];
if (empty($post_title) || empty($post_keywords) || empty($post_content) || empty($post_author))
{
echo '<script>alert("Some fields are missing")</script>';
}
else
{
if (!move_uploaded_file($image_tmp,"post_images/$post_image")) {
echo "Move Failed";
}
else
{
$insert_query = "INSERT INTO posts (post_title,post_date,post_author,post_image,post_keywords,post_content) VALUES ('$post_title','$post_date','$post_author','$post_image','$post_keywords','$post_content')";
$insert_post = mysqli_query($con,$insert_query);
if (!$insert_post){
echo mysqli_error($con);
}
else
{
echo '<h3 style="color:green">Post has been added successfully.</h3>';
}
}
}
}
?>