如何有效地查询具有多个条件的帖子？

Question

I have call-to-action posts that I want to display on my front page. I'd like to query these custom post types and display one of them that has a launch date < today's date, and an expiry date > today's date. If there aren't any that meet these conditions, I want to display a call-to-action that doesn't have an expiry date.

Is there a way I can query all call-to-action posts, then randomly display one that meets the first condition, and then if empty, the second condition?

I've successfully tried querying twice, one for each condition (see below). But I think I'd rather query the database once. As this way I can add further conditions as needed, without making innumerable queries. Or would this approach be ill-advised?

$today = date( "Ymd" );

// args
$condition1 = array(
    'posts_per_page'    => 1,
    'post_type'     => 'cta',
    'post-status'       => 'publish',
    'orderby'       => 'rand',
        'meta_query'        =>array(
            'relation' => 'AND',
            array(
                'key' => 'launch',
                'value' => $today,
                'compare' => '<'
            ),
                array(
                'key' => 'expiry',
                'value' => $today,
                'compare' => '>'
            ),
    )
);

$condition2 = array(
    'posts_per_page'    => 1,
    'post_type'     => 'cta',
    'post-status'       => 'publish',
    'orderby'       => 'rand',
    'meta_query'        =>array(
            array(
                'key' => 'launch',
                'value' => $today,
                'compare' => '<'
            ),
    )
);

// query
$cta1 = new WP_Query( $condition1 );
$cta2 = new WP_Query( $condition2 );

    if( !empty($cta1 -> have_posts()) ) :

        while( $cta1 -> have_posts() ) : $cta1 -> the_post(); global $post;

        // Display post with first condition

        endwhile; wp_reset_postdata();


    elseif( ( $cta2 -> have_posts() ) ) :

        while( $cta2 -> have_posts() ) : $cta2 -> the_post(); global $post;

        // Display post with second condition

        endwhile; wp_reset_postdata();

    endif;

Answer 1

You can use the advanced meta query option

$meta_query = array(
    'posts_per_page'    => 1,
    'post_type'     => 'cta',
    'post-status'       => 'publish',
    'orderby'       => 'rand',
        'meta_query'        =>array(
            'relation' => 'OR',
            array(
                'key' => 'launch',
                'value' => $today,
                'compare' => '<'
            ),
            array(
                'relation' => 'AND',
                array(
                    'key' => 'launch',
                    'value' => $today,
                    'compare' => '<'
                ),
                array(
                    'key' => 'expiry',
                    'value' => $today,
                    'compare' => '>'
                ),
            ),
    )
);