Using Custom Taxonomy Wordpress

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// Register Custom Taxonomy
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<?php
function pages_taxonomy() {
    register_taxonomy(
        'pages_cat',  //The name of the taxonomy. Name should be in slug form (must not contain capital letters or spaces).
        'page',          //post type name
        array(
            'hierarchical'      => true,
            'label'             => 'Page Category',  //Display name
            'query_var'         => true,
            'rewrite'           => array(
                'slug'          => 'page-category', // This controls the base slug that will display before each term
                'with_front'    => false // Don't display the category base before
                )
            )
    );
}
add_action( 'init', 'pages_taxonomy');
<?

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// Custom Taxonomy Query
=====================================================================================================

<?php
global $post;
$args = array( 'posts_per_page' => -1, 'post_type'=> 'staff', 'department_cat' => 'Commerical' );
$myposts = get_posts( $args );
foreach( $myposts as $post ) : setup_postdata($post); ?>

    // Your Post Content. Title, detail etc.

<?php endforeach; ?>