尝试以下操作：

global $wpdb;
$from_user = 2;
$to_user = 5;
$posts_table = $wpdb->prefix . \'posts\';
$users_table = $wpdb->prefix . \'users\';
$strQuery = "UPDATE `$posts_table` SET post_author = $to_user WHERE post_author = $from_user AND $posts_table.post_date < \'01/01/2013\' AND $wpdb->term_taxonomy.term_id IN (1,2,3) AND $wpdb->term_taxonomy.taxonomy = \'category\'";
echo $strQuery;
$wpdb->query($strQuery);

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$args = array(  
                \'category_name\' => \'Category 1\', 
                \'author_name=\' => \'Noor Ahmad Feroozi\',
                \'year\' => date(\'Y\'),
                \'month\' => date(\'n\')
              );

$posts = new WP_Query( $args );
if ( $posts->have_posts() ) : while ($posts->have_posts()) : $posts->the_post();
    wp_set_object_terms(get_the_ID(), \'Category 2\', \'category\');
endwhile; endif;