In wp_query, how can I order by a complex calculated or conditional fields?

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In wp_query, is it possible to build a complex query so I can order by a conditional or calculated fields?
what I’m trying to do is something like the next query in MySql: 

SELECT *, field1, field2
  case when field1+field2 > some_value then 1 else 2 end as my_alias
FROM my_table
ORDER BY my_alias ASC

I want to build queries like this one using wp_query, is this possible? if yes, how can I accomplish that?

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3 comments

  2. I don’t see any way to do this with a single WP_Query as meta_query doesn’t allow you such flexibility, though you can do three distinct queries then merge them (untested code):

    // Get ongoing events
$ongoing = new WP_Query(array(
    'post_type' => 'event',
    'meta_key' => 'date_from',
    'orderby' => 'meta_value',
    'order' => 'ASC',
    'meta_query' => array(
        'relation' => 'AND',
        array(
            'key' => 'date_from',
            'value' => date('Y-m-d'),
            'compare' => '<=',
            'type' => 'DATE'
        ),
        array(
            'key' => 'date_to',
            'value' => date('Y-m-d'),
            'compare' => '>=',
            'type' => 'DATE'
        )
    )
));
foreach($ongoing as $key => $ongoing_post) {
    $ongoing_post->event_status = 'ongoing';
    $ongoing[$key] = $ongoing_post;
}

// Get upcoming events
$upcoming = new WP_Query(array(
    'post_type' => 'event',
    'meta_key' => 'date_from',
    'orderby' => 'meta_value',
    'order' => 'ASC',
    'meta_query' => array(
        array(
            'key' => 'date_from',
            'value' => date('Y-m-d'),
            'compare' => '>',
            'type' => 'DATE'
        )
    )
));
foreach($upcoming as $key => $upcoming_post) {
    $upcoming_post->event_status = 'upcoming';
    $upcoming[$key] = $upcoming_post;
}

// Get past events
$past = new WP_Query(array(
    'post_type' => 'event',
    'meta_key' => 'date_from',
    'orderby' => 'meta_value',
    'order' => 'DESC',
    'meta_query' => array(
        array(
            'key' => 'date_to',
            'value' => date('Y-m-d'),
            'compare' => '<',
            'type' => 'DATE'
        )
    )
));
foreach($past as $key => $past_post) {
    $past_post->past_status = 'past';
    $past[$key] = $past_post;
}

// Merge'em all
$events = array_merge($ongoing, $upcoming, $past);

    The thing is to use meta_query to compare the meta values with the actual date (you may want to change the date format depending of how they are stored in date_from and date_to fields), and do a little loop right after to add a property to all post object with the right event_status which you can work with when displaying posts.

    Maybe there is a clever way to achieve this through WP_Query filters but it would need more in-depth investigation inside WP_Query source code as it is not really documented inside the codex.

  3. I thing You use, and try this,

    <?php
    global $wpdb;
    $result = $wpdb->get_results("SELECT *, field1, field2 case when field1+field2 > some_value then 1 else 2 end as my_alias FROM my_table ORDER BY my_alias ASC");
    print_r($result);
?>

    Look at this Click Here

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