Get post id in wordpress action?

Question

I have this code

add_action( 'delete_post', 'my_delete_function' );
 function my_delete_function() { 
   global $wpdb;
   $wpdb->query("
    DELETE FROM wp_votes WHERE post=".$thePostID."
;);
 }

How can I get the id of the post being deleted?

Additionally, will this still work if multiple posts are deleted in the admin?

Answer 1

I haven't tested so I'm providing you with two possibilities, Inside a loop, use the following:

$post_id = get_the_ID();

Outside a loop, use the following:

global $wp_query;
$post_id = $wp_query->post->ID;

Or:

global $post;
$post_id = $post->ID

Or you can pass the post ID in a function, much like

function my_function($post_id){
    // code
}

Answer 2

Add a parameter to your function, which will be passed the ID of the current post being deleted.

add_action( 'delete_post', 'my_delete_function' );
function my_delete_function( $post_id /* <- ID of post being deleted */ )
{ 
    global $wpdb;
    $wpdb->query( $wpdb->prepare( "DELETE FROM {$wpdb->prefix}_votes WHERE post = %d", $post_id ) );
}

Using any external variable (like a global in @Asko's answer) removes any guarantee that the post actually being deleted is the one you're working on within your function - it could either fail completely, or even delete data for the wrong post!