返回具有多个元键的 wpdb 并按元值排序答案

【问题标题】：Return wpdb with multiple meta keys and sort by a meta_value返回具有多个元键的 wpdb 并按元值排序
【发布时间】：2012-04-18 23:26:49
【问题描述】：

我正在尝试使用 wordpress wpdb 类返回具有元键的两个值之一的自定义帖子，然后按第三个元值对这些帖子进行排序。我可以获得我想要的帖子，但我似乎无法弄清楚如何按照我想要的方式对它们进行排序。

我目前的功能是：

function artists_search_country($country_alt){
    global $wpdb;
    $querystr = "
        SELECT wposts.*
        FROM $wpdb->posts wposts, $wpdb->postmeta wpostmeta
        WHERE wposts.ID = wpostmeta.post_id
        AND ((wpostmeta.meta_key = '_artist_country' AND wpostmeta.meta_value = '$country_alt')
        OR (wpostmeta.meta_key = '_artist_country_sub' AND wpostmeta.meta_value = '$country_alt'))
        AND wposts.post_type = 'artists'
        AND wposts.post_status = 'publish'
    ";
    $myposts = $wpdb->get_results($querystr, OBJECT);
    return $myposts;
}

我想做这样的事情：

function artists_search_country($country_alt){
    global $wpdb;
    $querystr = "
        SELECT wposts.*
        FROM $wpdb->posts wposts, $wpdb->postmeta wpostmeta
        WHERE wposts.ID = wpostmeta.post_id
        AND ((wpostmeta.meta_key = '_artist_country' AND wpostmeta.meta_value = '$country_alt')
        OR (wpostmeta.meta_key = '_artist_country_sub' AND wpostmeta.meta_value = '$country_alt'))
        AND wposts.post_type = 'artists'
        AND wposts.post_status = 'publish'
        ORDER BY (wpostmeta.meta_key = '_artist_artist_last_name' AND wpostmeta.value) ASC
    ";
    $myposts = $wpdb->get_results($querystr, OBJECT);
    return $myposts;
}

请原谅ORDER BY 行上的糟糕语法，但我只是不知道如何处理这个问题，我尝试的一切都会破坏查询。任何帮助将不胜感激，因为我在 SQL 查询方面没有太多经验。

【问题讨论】：

标签： php sql sql-order-by wordpress

【解决方案1】：

试试这个 SQL 语句：

SELECT wposts.*, l.meta_value as artist_last_name
FROM $wpdb->posts wposts
    join $wpdb->postmeta wpostmeta
    on wposts.ID = wpostmeta.post_id
    join $wpdn->postmeta l
    on wposts.ID = l.post_id
    and l.meta_key = '_artist_artist_last_name'
WHERE
(( wpostmeta.meta_key = '_artist_country' AND wpostmeta.meta_value = '$country_alt')
OR (wpostmeta.meta_key = '_artist_country_sub' AND wpostmeta.meta_value = '$country_alt') )
AND wposts.post_type = 'artists'
AND wposts.post_status = 'publish'
ORDER BY l.meta_value ASC

您需要为艺术家的姓氏进行第二次加入。

另一个建议是利用 Wordpress 的$wpdb->prepare，如下所示：

$querystr = "
SELECT wposts.*, l.meta_value as artist_last_name
FROM $wpdb->posts wposts
    join $wpdb->postmeta wpostmeta
    on wposts.ID = wpostmeta.post_id
    join $wpdn->postmeta l
    on wposts.ID = l.post_id
    and l.meta_key = '_artist_artist_last_name'
WHERE
(( wpostmeta.meta_key = '_artist_country' AND wpostmeta.meta_value = %s)
OR (wpostmeta.meta_key = '_artist_country_sub' AND wpostmeta.meta_value = %s) )
AND wposts.post_type = 'artists'
AND wposts.post_status = 'publish'
ORDER BY l.meta_value ASC
";
$myposts = $wpdb->get_results($wpdb->prepare( $querystr, $country_alt, $country_alt ), OBJECT);

希望这会有所帮助。

【讨论】：