Database Query not working, Wordpress

Question

I've been following a tutorial by Steve Marks which goes throught adding information from posts to a new Database Table as well as the usual postmeta one. However no matter what I try, It will not store the information in the new table, can anyone see where I'm going wrong?

Tutorial is available here: http://biostall.com/performing-a-radial-search-with-wp_query-in-wordpress my post type is festival-event and i made the names of my custom post types the same as in the function to see if I was missing something there.

The SQL I used to creat the table in the db was:

CREATE TABLE IF NOT EXISTS `lat_lng_post` (  
  `post_id` bigint(20) unsigned NOT NULL,  
  `lat` float NOT NULL,  
  `lng` float NOT NULL  
) ENGINE=InnoDB;  

And the function in my functions.php file is:

function save_lat_lng( $post_id )   
{  
    global $wpdb;  

    // Check that we are editing the right post type  
    if ( 'location' != $_POST['festival-event'] )   
    {  
        return;  
    }  

    // Check if we have a lat/lng stored for this property already  
    $check_link = $wpdb->get_row("SELECT * FROM lat_lng_post WHERE post_id = '" . $post_id . "'");  
    if ($check_link != null)   
    {  
        // We already have a lat lng for this post. Update row  
        $wpdb->update(   
        'lat_lng_post',   
        array(   
            "lat" => $_POST['lat_field_name'],  
            "lng" => $_POST['lng_field_name']  
        ),   
        array( "post_id" => $post_id ),   
        array(   
            "%f",  
            "%f"  
        )  
        );  
    }  
    else  
    {  
        // We do not already have a lat lng for this post. Insert row  
        $wpdb->insert(   
        "lat_lng_post",   
        array(   
            "post_id" => $post_id,  
            "lat" => $_POST['lat_field_name'],  
            "lng" => $_POST['lng_field_name']  
        ),   
        array(   
            "%d",   
            "%f",  
            "%f"  
        )   
        );  
    }  

}  
add_action( 'save_post', 'save_lat_lng' );

I've been researching load on what the problem could be but no luck whatsoever, I'm really stuck. Attached is images of PHPMyAdmin so you can see the db

Answer 1

Although the answer from @GentlemanMax was relatively useful, the actual mistake was rookie error and by me and was solved on another site, The answer was this

if ( 'festival-event' != $_POST['post_type'] )

rather than this

if ( 'post_type' != $_POST['festival-event'] )

Answer 2

Without seeing the tutorial you're following it is hard to say what the issue is. However, this block strikes me as a very strange way to check the post type:

if ( 'location' != $_POST['festival-event'] )   
{  
    return;  
}  

Try changing that block to something like this:

if ( get_post_type( $post_id ) != 'festival-event'] )   
{  
    return;  
}  

Alternatively, if you are using WordPress 3.7 or above you can remove that block entirely and hook to save_post_festival-event. In that scenario, your last line would look like

add_action('save_post_festival-event', 'save_lat_lng')

EDIT: To make this work with ACF

function save_lat_lng( $post_id )   
{  


    // Check that we are editing the right post type  
    if ( get_post_type($post_id) != 'festival-event' || empty($_POST['acf'] ))   
    {  
        return;  
    }  

    global $wpdb; 
    $fields = $_POST['acf'];

    // Check if we have a lat/lng stored for this property already  
    $check_link = $wpdb->get_var($wpdb->prepare(
        "SELECT COUNT(*) FROM lat_lng_post WHERE post_id = %d", $post_id
    ));  
    if (!empty($check_link))
    {  
        // We already have a lat lng for this post. Update row  
        $wpdb->update(   
            'lat_lng_post',   
            array(   
                "lat" => $fields['lat_field_name'],  
                "lng" => $fields['lng_field_name']  
            ),   
            array( "post_id" => $post_id ),   
            array(   
                "%f",  
                "%f"  
            )  
        );  
    }  
    else  
    {  
        // We do not already have a lat lng for this post. Insert row  
        $wpdb->insert(   
            "lat_lng_post",   
            array(   
                "post_id" => $post_id,  
                "lat" => $field['lat_field_name'],  
                "lng" => $field['lng_field_name']  
            ),   
            array(   
                "%d",   
                "%f",  
                "%f"  
            )   
        );  
    }  
}  
add_action( 'acf/save_post', 'save_lat_lng', 1 );

*Note, you will have to change lat_field_name and lng_field_name to whatever you set them to when you created the fields via ACF.

I also changed your query to make use of $wpdb->prepare

While not related to this issue, I would recommend against creating a custom table without a wordpress prefix, in your case wp_