WordPress的posts_orderby过滤器与插件中的自定义表 [英] wordpress posts_orderby filter with custom table in plugin

问题描述

我正在开发一个Wordpress插件，需要使用我用该插件创建的自定义表格对网站的帖子进行排序.

I'm developing a Wordpress plugin and need to order the posts of the site with the custom table that I created with my plugin.

我不想更改主题中的代码，所以我在法典上找到了过滤器posts_orderby和posts_join(在此处找到: https://codex.wordpress.org/Custom_Queries ).

I don't want to alter the code within the theme so I found on codex the filters posts_orderby and posts_join (found here: https://codex.wordpress.org/Custom_Queries).

自定义表具有以下值:

ID    slug    price 

，并在我添加以下行的插件文件中:

and in the plugin file where I added these lines:

add_filter('posts_orderby','custom_orderby');
add_filter('posts_join','custom_join');

function custom_join($join){
    global $wpdb;
    $customTable = $wpdb->prefix.'custom_table';

    if(!is_admin()){
        $join .= " LEFT JOIN $customTable ON $wpdb->postmeta.meta_value = $customTable.slug";
    }
    return $join;
}
function custom_orderby($orderby_statement){
    global $wpdb;
    $customTable = $wpdb->prefix.'custom_table';

    if(!is_admin()){
        $orderby_statement = "$customTable.price DESC"; 
    }
    return $orderby_statement;
}

当我刷新索引页面时，它会显示以下错误消息:

When I refresh the index page it gives me this error message:

No Results Found

The page you requested could not be found. Try refining your search, or use the navigation above to locate the post.

我尝试使用以下代码直接在数据库中进行查询:

I tried to do the query directly on my database with this code:

SELECT * FROM wp_posts t1
    LEFT JOIN wp_postmeta t2 ON t1.ID = t2.post_id
    LEFT JOIN wp_custom_table t3 ON t2.meta_value = t3.slug

ORDER BY t3.price DESC

它有效.

所以我的插件文件中编写的代码出了点问题，但我无法弄清楚.

So there's something wrong in the code written in my plugin file but I can't figure it out.

推荐答案

好，我解决了.

问题在于发布查询不包含postmeta表，因此我将其添加到custom_join函数中，如下所示:

The problem is that the post query doesn't include the postmeta table, so I added it on the custom_join function, like this:

add_filter('posts_join','custom_join');
add_filter('posts_orderby','custom_orderby');

function custom_join($join){
    global $wpdb;
    $customTable = $wpdb->prefix."custom_table";

    if(!is_admin){
        $join .= "LEFT JOIN $wpdb->postmeta p1 ON $wpdb->posts.ID = p1.post_id";
        $join .= "LEFT JOIN $customTable p2 ON p1.meta_value = p2.slug";
    }

    return $join;
}

function custom_orderby($orderby_statement){
    global $wpdb;

    if(!is_admin){
        $orderby_statement = "p2.price DESC, $wpdb->posts.post_date DESC";
    }

    return $orderby_statement;
}

我还添加了posts_groupby过滤器，因为新查询为我提供了重复的帖子(很多重复的帖子).

I added also the posts_groupby filter because the new query gave me duplicated posts (lots of duplicated posts).

代码如下:

add_filter('posts_groupby','custom_groupby');

function custom_groupby($groupby){
    global $wpdb;

    if(!is_admin){
       $groupby = "$wpdb->posts.ID";
    }

    return $groupby;
}

一切都写在插件文件中，但您也可以写在主题的function.php文件中.

Everything is written in the plugin file, but you can write also in the function.php file of your theme.

如果要在前端仅看到自定义查询，请记住包含if(!is_admin)语句.

Remember to include the if(!is_admin) statement if you want to see the custom query only on front end.

这篇关于WordPress的posts_orderby过滤器与插件中的自定义表的文章就介绍到这了，希望我们推荐的答案对大家有所帮助，也希望大家多多支持IT屋！