Igor Belikov

$(function() {
  $('.btn-news').click(function(e) {
    var $current = $('.content-block.active');
    $current.removeClass('active');
    $current.next('.content-block').addClass('active');
  });
});

// основные категории
$categories = get_categories( array(
    'parent'  => 0
) );
foreach ( $categories as $category ) {
    // подкатегории
    $sub_categories = get_categories( array(
        'parent'  => $category->term_id
    ) );
    foreach ( $sub_categories as $sub_category ) {
        // записи
        $posts = get_posts( array( 
            'category' => $sub_category->term_id,
            'posts_per_page' => 5,
            'orderby' => 'date',
        ) );
        foreach ( $posts as $post ) {
            // вывод поста и фото
        }
    }
}

SELECT `name`, COUNT(*) as `c`
FROM `table`
GROUP BY `name`
HAVING `c` > 1

class Department extends \yii\db\ActiveRecord {
  /**
   * @return \yii\db\ActiveQuery
   */
  public function getBuildings() {
    return $this->hasMany(Building::className(), ['department_id' => 'id']);
  }
  // ...
}

class Building extends \yii\db\ActiveRecord {
  /**
   * @return \yii\db\ActiveQuery
   */
  public function getDepartment() {
    return $this->hasOne(Department::className(), ['id' => 'department_id']);
  }
  /**
   * @return \yii\db\ActiveQuery
   */
  public function getRooms() {
    return $this->hasMany(Room::className(), ['building_id' => 'id']);
  }
  // ...
}

var_dump($building->department);
var_dump($building->rooms);

class Room extends \yii\db\ActiveRecord {
  /**
   * @return \yii\db\ActiveQuery
   */
  public function getBuilding() {
    return $this->hasOne(Building::className(), ['id' => 'building_id']);
  }
  // ...
}