I have an author page, i want to list post from current author's categories.

e.g. Im viewing John's page, and John did write Sport, Tech, News, Computer category

Then my code list from this(Sport, Tech, News, Computer) categories list random 10 post.

Regards

My code

<?php global $post, $wpdb;
$author_id = $post->post_author;
$categories = $wpdb->get_results("
    SELECT DISTINCT(terms.term_id) as ID, terms.name, terms.slug
    FROM $wpdb->posts as posts
    LEFT JOIN $wpdb->term_relationships as relationships ON posts.ID = relationships.object_ID
    LEFT JOIN $wpdb->term_taxonomy as tax ON relationships.term_taxonomy_id = tax.term_taxonomy_id
    LEFT JOIN $wpdb->terms as terms ON tax.term_id = terms.term_id
    WHERE 1=1 AND (
        posts.post_status = 'publish' AND
        posts.post_author = '$author_id' AND
        tax.taxonomy = 'category' )
    ORDER BY terms.name ASC
");

foreach($categories as $category) : 
$catnumber = $category->ID.',';
endforeach;?>
<?php 

$args = array(
'category__and' => array( $catnumber )
, 'showposts'=> '10'
);

$my_query = new WP_Query( $args );
?>
<ul>
<?php while ( $my_query->have_posts() ) : $my_query->the_post(); ?>
    <li>
        <a href="<?php the_permalink(); ?>"><?php the_title(); ?></a>  
    </li>
<?php endwhile; ?>
<ul>
<?php wp_reset_postdata(); ?>