function wt_get_category_count($input = '') {
	global $wpdb;
	if($input == '')
	{
		$category = get_the_category();
		return $category[0]->category_count;
	}
	elseif(is_numeric($input))
	{
		$SQL = "SELECT $wpdb->term_taxonomy.count FROM $wpdb->terms, $wpdb->term_taxonomy WHERE $wpdb->terms.term_id=$wpdb->term_taxonomy.term_id AND $wpdb->term_taxonomy.term_id=$input";
		return $wpdb->get_var($SQL);
	}
	else
	{
		$SQL = "SELECT $wpdb->term_taxonomy.count FROM $wpdb->terms, $wpdb->term_taxonomy WHERE $wpdb->terms.term_id=$wpdb->term_taxonomy.term_id AND $wpdb->terms.slug='$input'";
		return $wpdb->get_var($SQL);
	}
}

It can be called in three different ways…

1. Just call the function within The Loop and it will return the count of the first category within the current post.

<?php echo wt_get_category_count(); ?>

2. Use the function with an ID and it will return the count of the first category within the post ID.

<?php echo wt_get_category_count(1); ?>

3. Use the function with a slug / nicename and it will return the count of the first category within the post slug / nicename.

<?php echo wt_get_category_count('hello-world'); ?>

To get all new functions/template tags, install my plugin WP Extra Template Tags.

Put the following code to the functions.php in your Wordpress theme folder.

function wt_get_depth($id = '', $depth = '', $i = 0)
{
	global $wpdb;
	global $post;

	if($depth == '')
	{
		if(is_page())
		{
			if($id == '')
			{
				$id = $post->ID;
			}
			$depth = $wpdb->get_var("SELECT post_parent FROM $wpdb->posts WHERE ID = '".$id."'");
			return wt_get_depth($id, $depth, $i);
		}
	}
	elseif($depth == "0")
	{
		return $i;
	}
	else
	{
		$depth = $wpdb->get_var("SELECT post_parent FROM $wpdb->posts WHERE ID = '".$depth."'");
		$i++;
		return wt_get_depth($id, $depth, $i);
	}
}

Call the function like this in your theme:

<?php echo wt_get_depth(); ?>

or if you want to choose a custom page:

<?php echo wt_get_depth(3); ?>

Here is a way do use the function:

<?php if (wt_get_depth() == 2)
{
	echo "This page is a grand grandchild";
}
?>

If you need a function like is_child() or is_grandchild(), create an is_child() function like this:

function wt_is_child($id = '')
{
	if(_get_depth($id)>0)
	{
		return true;
	}
}

or the is_grandchild() function:

function wt_is_grandchild($id = '')
{
	if(_get_depth($id)>1)
	{
		return true;
	}
}

and call them like this:

<?php if (wt_is_child())
{
echo "This is a child page";
}
?>

or

<?php if (wt_is_grandchild())
{
echo "This is a grandchild page";
}
?>

To get all new functions/template tags, install my plugin WP Extra Template Tags.

For include or exclude pages you need the ID. For me it feels better to use the page name instead, simply because the ID can change but the name does not. I have written a function fix this issue.

The function converts a page name to a page ID. You can use it however you like but in the example I used it with the wp_list_pages() function.

function wt_get_ID_by_page_name($page_name)
{
	global $wpdb;
	$page_name_id = $wpdb->get_var("SELECT ID FROM $wpdb->posts WHERE post_name = '".$page_name."'");
	return $page_name_id;
}

Call the function in your theme:

<?php wp_list_pages('include='.wt_get_ID_by_page_name('about') ); ?>

If you just need to display the ID of a page, call the function like this instead:

<?php echo wt_get_ID_by_page_name('about'); ?>

To get all new functions/template tags, install my plugin WP Extra Template Tags.

Put the following code to the functions.php in your theme folder.

function wt_get_permalink_by_name($page_name)
{
	global $post;
	global $wpdb;
	$pageid_name = $wpdb->get_var("SELECT ID FROM $wpdb->posts WHERE post_name = '".$page_name."'");
	return get_permalink($pageid_name);
}

Call the function like this in your theme:

<a href="<?php echo wt_get_permalink_by_name('about'); ?>">About</a>

To get all new functions/template tags, install my plugin WP Extra Template Tags.

<?php echo get_the_content(); ?>
<?php the_content(); ?>

For me and others that can be a problem if you expect them to behave the same. I looked into the Wordpress core and found a solution. Put this code into your functions.php in your theme folder.

function get_the_content_with_formatting ($more_link_text = '(more...)', $stripteaser = 0, $more_file = '') {
	$content = get_the_content($more_link_text, $stripteaser, $more_file);
	$content = apply_filters('the_content', $content);
	$content = str_replace(']]>', ']]>', $content);
	return $content;
}

In your theme, call the function within the loop:

<?php get_the_content_with_formatting(); ?>

To get more new functions/template tags, install my plugin WP Extra Template Tags.

Here is the solution recommended by the Wordpress team. It displays all the category IDs hooked to the post.

<?php
foreach((get_the_category()) as $category) {
    echo $category->cat_ID . ' ';
} ?>

It’s a bit long and complicated if you just need the first category. The function below is an alternative. It returns the first category ID as a string. Put this function in your functions.php within your theme folder:

function wt_get_category_ID() {
	$category = get_the_category();
	return $category[0]->cat_ID;
}

Call the function below by placing it within the loop in your theme:

wt_get_category_ID();

Short and sweet, is’nt it?

To get all new functions/template tags, install my plugin WP Extra Template Tags.

function wt_get_user_name()
{
	global $userdata;
	get_currentuserinfo();
	return $userdata->user_login;
}

Now you can print it out to see that you get a string value (this will only work when you are logged in). Put the code below somewhere in your theme to do so.

<?php echo 'Welcome ' . wt_get_user_name(); ?>

To check if a specific user is logged in try this:

<?php
if(wt_get_user_name() == 'Adam')
{
	echo 'You have all the rights to visit this page!'
}
else
{
	echo 'You do not have permission to view this page!'
}
?>

To get all new functions/template tags, install my plugin WP Extra Template Tags.

I have created a function called “Delete Post Link”. If you are logged in you will see a link which allows you to delete the current page or post, even without visiting admin.

Warning! You should be very careful using this function!

function wp_delete_post_link($link = 'Delete This', $before = '', $after = '')
{
	global $post;
	if ( $post->post_type == 'page' ) {
		if ( !current_user_can( 'edit_page', $post->ID ) )
			return;
	} else {
		if ( !current_user_can( 'edit_post', $post->ID ) )
			return;
	}
	$link = "<a href='" . wp_nonce_url( get_bloginfo('url') . "/wp-admin/post.php?action=delete&amp;post=" . $post->ID, 'delete-post_' . $post->ID) . "'>".$link."</a>";
	echo $before . $link . $after;
}

I recommend you to put the function into your functions.php file in your theme folder. When done just put the function into your theme like this:

wp_delete_post_link('Delete This', '<p>', '</p>')

To get all new functions/template tags, install my plugin WP Extra Template Tags.