Sort WordPress Meta Field By Date Using WP_Query

I have posts with meta data that I want to sort by 'LiveStreamDate'. Format of meta field is: yyyy/mm/dd.

My current code below:

$recent = new WP_Query('cat='.$spcatid.'&paged=' . $paged); while($recent->have_posts()) : $recent->the_post();
$tmpLiveTime = get_post_custom_values("LiveStreamTime");
$tmpLiveDate = get_post_custom_values("LiveStreamDate");
$tmpLiveCompetition = get_post_custom_values("LiveStreamCompetition");
$tmpLiveMatch = get_p开发者_StackOverflow中文版ost_custom_values("LiveStreamMatch");

NORMAL LOOP STUFF HERE

Any ideas? I have looked through the WP_QUERY examples using meta fields and values - but how to construct the query (or add another query) to end up with data sorted by meta field by value of it's date?

Cheers BK

---

You can use the follow example:

add_filter('posts_orderby', 'my_filter_posts_orderby' );
$query = new WP_Query( array(
    'meta_key' => 'LiveStreamDate',
    'cat' => $spcatid,
    'paged' => $paged,
) );
remove_filter( 'posts_orderby', 'my_filter_posts_orderby' );

function my_filter_posts_orderby( $orderby )
{
    global $wpdb;
    $orderby = $wpdb->postmeta . '.meta_value DESC, ' . $orderby;
    return $orderby;
}

while($query->have_posts()) { 
$query->the_post();
echo get_post_custom_values("LiveStreamDate");
}

The list of possible parameters are in WordPress file

/wp-includes/query.php

inside this function:

/**
     * Fills in the query variables, which do not exist within the parameter.
     *
     * @since 2.1.0
     * @access public
     *
     * @param array $array Defined query variables.
     * @return array Complete query variables with undefined ones filled in empty.
     */
    function fill_query_vars($array) {
        $keys = array(
            'error'
            , 'm'
            , 'p'
            , 'post_parent'
            , 'subpost'
            , 'subpost_id'
            , 'attachment'
            , 'attachment_id'
            , 'name'
            , 'static'

(...)