我正在运行以下查询，试图获取大量帖子的数据和相关元数据：

SELECT wp_posts.post_title, wp_posts.post_date,
    wp_posts.ID, wp_postmeta.post_id, wp_postmeta.meta_key
    FROM wp_postmeta
    INNER JOIN wp_posts
    ON wp_postmeta.post_id=wp_posts.id
    WHERE wp_posts.post_status = \'publish\'
    LIMIT 5

返回以下内容：

Array
(
    [0] => stdClass Object
        (
            [post_title] => Hello world!
            [post_date] => 2015-11-11 08:44:54
            [ID] => 1
            [post_id] => 1
            [meta_key] => _edit_lock
        )

    [1] => stdClass Object
        (
            [post_title] => Home
            [post_date] => 2015-11-11 08:44:54
            [ID] => 2
            [post_id] => 2
            [meta_key] => _wp_page_template
        )

    [2] => stdClass Object
        (
            [post_title] => Home
            [post_date] => 2015-11-11 08:44:54
            [ID] => 2
            [post_id] => 2
            [meta_key] => _edit_last
        )
...

但现在我意识到我需要一个更复杂的查询，因为我想要的是以下内容：

Array
(
    [0] => stdClass Object
        (
            [post_title] => Hello world!
            [post_date] => 2015-11-11 08:44:54
            [ID] => 1
            [post_id] => 1
            [meta] => array(
                \'_wp_page_template\' => \'home.php\',
                \'_edit_last\' => 2015-11-11 08:44:54,
            )
        )

    [1] => stdClass Object
        (
            [post_title] => Home
            [post_date] => 2015-11-11 08:44:54
            [ID] => 2
            [post_id] => 2
            [meta] => array(
                \'_wp_page_template\' => \'home.php\',
                \'_edit_last\' => 2015-11-11 08:44:54,
            )
        )

    [2] => stdClass Object
        (
            [post_title] => About us
            [post_date] => 2015-11-11 08:44:54
            [ID] => 3
            [post_id] => 3
            [meta] => array(
                \'_wp_page_template\' => \'home.php\',
                \'_edit_last\' => 2015-11-11 08:44:54,
            )
        )

get_post_meta($postid);

<?php
    $custom = new WP_Query(array("posts_per_page" => -1))
    if( $custom->have_posts() ) {
        while ( $custom->have_posts() ) {
            the_post();
            $data = get_post_meta(get_the_ID());
        }
    } else {
        /* No posts found */
    }
?>

SELECT wp_posts.post_title, wp_posts.post_date,
wp_posts.ID, wp_postmeta.post_id, wp_postmeta.meta_key, 
GROUP_CONCAT(wp_postmeta.meta_key SEPARATOR \':\') AS meta_keys

FROM wp_postmeta
INNER JOIN wp_posts
ON wp_postmeta.post_id=wp_posts.id
WHERE wp_posts.post_status = \'publish\'
GROUP BY wp_postmeta.post_id
LIMIT 5

$meta_keys = explode(\':\', $item->meta_keys);