php - How correct code in WordPress sidebar to show only posts from last 1 month from category -

i started work on 1 website after developer , don't understand how make popular widget show posts last 3 months categories(1 month category news). see there switch statement should it, not doing job. how make intervals correctly?

function getsomepost($category,$postsperpage=3) {         global $post;          $args = array(             'category_name'=>$category,             'posts_per_page'=>$postsperpage,             'post_type'=>'post',             'post_status'=>'publish',             'post__not_in'=>array($post->id),             'orderby'=>'rand',         );          switch ($category)         {             case 'news':                 $args['interval'] = '1 month';                 break;             case 'analysis':                 $args['interval'] = '3 month';                 break;             case 'reports':                 $args['interval'] = '3 month';                 break;         }          $query = new wp_query($args);          if ( $query->have_posts() ) {                while ( $query->have_posts() ) {                $query->the_post();                $postthumbclass = 'no-thumb';                ?>                    <div <?php post_class(array('wp-post-entry', 'sidebar-post' )); ?>>                     <?php if(has_post_thumbnail ()):?>                         <?php $postthumbclass = '' ?>                         <div class="wp-post-thumbnail">                             <a href="<?php the_permalink() ?>">                                 <?php the_post_thumbnail(array(70,70)); ?>                             </a>                         </div>                      <?php endif; ?>                       <div class="wp-post-full-content <?php echo $postthumbclass ?> ">                         <h3 class="wp-post-title"><a href="<?php the_permalink(); ?>"><?php the_title(); ?></a></h3> <!--                         <div class="post-content">                             <?php the_excerpt() ?>                         </div> //-->                     </div>                 </div>                }         }      } 

update

i trying replace inside switch

case 'news':                 $args['interval'] = '1 month';                 break; 

with

 case 'news':     // create new filtering function add our clause query     function filter_where( $where = '' ) {         // posts in last 30 days         $where .= " , post_date > '" . date('y-m-d', strtotime('-30 days')) . "'";         return $where;     }      add_filter( 'posts_where', 'filter_where' );     $query = new wp_query( $query_string ); //i tried $args ,     remove_filter( 'posts_where', 'filter_where' );     break; 

and

case 'analysis':                     $args['interval'] = '3 month';                     break; 

with

case 'analysis': // create new filtering function add our clause query function filter_where( $where = '' ) {     // posts in last 30 days     $where .= " , post_date > '" . date('y-m-d', strtotime('-90 days')) . "'";     return $where; }  add_filter( 'posts_where', 'filter_where' ); $query = new wp_query( $query_string ); remove_filter( 'posts_where', 'filter_where' ); break; 

you may use time parameter in $args query particular period. see time parameter documentation.

example:

// returns posts current week $week = date('w'); $year = date('y'); $query = new wp_query( 'year=' . $year . '&w=' . $week );