Get posts using WP_Query

Question

I want to show posts using WP_Query functions. Also I want to add random order.

So I try

<?php
  $temp = $wp_query; 
  $wp_query= null;
  $args = array(
        'orderby' => 'rand',
  ); 
  $wp_query = new WP_Query($args);
  $wp_query->query('showposts=8' . '&paged='.$paged );
  while ($wp_query->have_posts()) : $wp_query->the_post();
?>

I can see 8 posts but it seems 'orderby' => 'rand' doesn't work.

Answer 1

It's quite some time since I worked with WordPress, but it seems to me that:

You're executing the query twice.

• First when you pass $args to the constructor during instantiation.

• Second when you call query().

With this, you're essentially overwriting the first query (the one that contains the orderby=rand).

The documentation of WP_Query mentions that get_posts() is called if you use a parameter in the constructor, and it shouldn't be called twice:

&get_posts() – Fetch and return the requested posts from the database. Also populate $posts and $post_count. Note: This is called during construction if WP_Query is constructed with arguments. It is not idempotent and should not be called more than once on the same query object. Doing so may result in a broken query.

And the query() method's documentation states that it calls get_posts(), therefore it's called twice:

&query( $query ) – Call parse_query() and get_posts(). Return the results of get_posts().

The solution:

• You should either put everything in $args, or
• add the orderby parameter too to the $wp_query->query(..) call.

Answer 2

Take a look at the WP_Query class reference and work yourself up from there. Try the basic examples, play around with the parameters until you get a feel for how WP_Query and the loop works.

https://codex.wordpress.org/Class_Reference/WP_Query

The reason your query isn't working is that you are not passing the parameters correctly (use the args array for all) and using deprecated params.