WordPress – How to Get the Post ID

There are various locations throughout your theme where you might need to get the post ID. For instance you may have a widget in the sidebar that needs the ID or some place in the Header or the Footer that needs the ID. The following is a list of different ways to get the ID.

Inside the loop:
This is a WordPress function for use in the Loop:

the_ID()

or, You can build a function and put in in functions.php

function getthe_loop_postID() {
     global $post;
     $thePostID = $post->ID;
}

In single.php outside of the loop:
You can build a function and put it in functions.php with

function getthe_single_postID() {
     global $wp_query;
     $thePostID = $wp_query->post->ID;
}

or you can use post->ID within the single.php template

If you are going to use post->ID within the header or the footer but want it to display on the single post page. You can use:

if is_single() {
     echo post-ID;
}

or what ever it is you want to do with it.

You can use other SQL commands with the post->ID query as well.

For Example:
If you want to see if the post is a particular post use:

post->ID WHERE ID = 17

For the most recent post use:

$post->ID ORDER BY post_date ASC LIMIT 1

For the oldest post use:

$post->ID ORDER BY post_date DESC LIMIT 1