Query posts and filter at query time by value of custom meta

Question

I have a wordpress query for a custom post type, but I want to filter the results depending on the value of a custom meta.

    <?php $my_query = new WP_Query('post_type=prizes&showposts=3&orderby=rand');
while ($my_query->have_posts()) : $my_query->the_post(); 
$do_not_duplicate = $post->ID; $my_meta = get_post_meta($post->ID,'_my_meta',TRUE); ?>

<?php if(($calctotalnew - number_format($cart->total,2)) >= $my_meta['pointsvalue']){ ?>

    <div class="footerprizecontainer">
        <a href="<?php the_permalink();?>"><span class="footerprizetitle"><?php the_title();?></span></a>

        <div class="footerprizevalue">
            <h2><?php echo $my_meta['pointsvalue'];?></h2>
        </div>

        <div align="center">
            <a href="<?php the_permalink();?>"><?php the_post_thumbnail('thumb');?></a>
        </div>

    </div>

<?php } 

Thats my code. Bascially the IF statement in the loop filters the results, but I need them filtering as they are queried because it doesnt always show exactly 3 posts (as some posts will have a value above what if filtered in the IF statement.

Any thoughts?

Thanks

Answer 1

This is super easy to do with meta_querys:

$args = array(
    //basics
    'post_type'      => 'prizes',   // from question
    'post_status'    => 'publish',  // you didn't have this, but it's good practice
    'posts_per_page' => 3,           // I don't know where you got 'showposts', but that's WAY old

    //order
    'orderby'        => 'rand',

    //meta query
    'meta_query'     => array(
        array(
            'key'     => $my_meta['pointsvalue'],
            'value'   => ( $calctotalnew - number_format( $cart->total, 2 ) ),
            'compare' => '<=',
            'type'    => 'NUMERIC'
        )
    )
);

$my_query = new WP_Query( $args );

Also, your $do_not_duplicate is completely non-sensical. It's setup but never called, you probably want to address that.

I filled in some of the details for you, they may not be right. The documentation on WP_Query will help you get everything correct.