关于mysql：通过new wpdb更改数据库后使用wp_query

Use wp_query after changing database via new wpdb

我正在尝试使用 wordpress 从其他数据库访问自定义帖子。为此，我更改了当前的 $wpdb 全局变量：

1 2	$wpdb = new wpdb( $user, $pass, $db, $host ); $wpdb->show_errors();

这不会显示任何错误，但是当我尝试使用 WP_Query:

1 2	$args = array('post_type'=>'produtos'); $newloop = new WP_Query($args);

我收到以下错误：

WordPress database error: [You have an error in your SQL syntax; check the manual that corresponds to your MySQL server version for the right syntax to use near 'FROM WHERE 1=1 AND .post_type = 'produtos' AND (.post_status = 'publish' OR .' at line 1]

SELECT SQL_CALC_FOUND_ROWS .ID FROM WHERE 1=1 AND .post_type = 'produtos' AND (.post_status = 'publish' OR .post_author = 1 AND .post_status = 'private') ORDER BY .post_date DESC LIMIT 0, 10

如果我使用 $wpdb->get_results() 和 $wpdb->get_var() 函数，我可以实现我想要的：

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$wpdb = new wpdb( $user, $pass, $db, $host );
$rows = $wpdb->get_results("SELECT * FROM wp_posts where post_type='produtos' AND post_status='publish'");
foreach ($rows as $produto) {
$id = $produto->ID;
$title = $produto->post_title;
$valor = $wpdb->get_var("SELECT meta_value FROM wp_postmeta WHERE meta_key = 'preco' AND post_id = $id");
$url_id = $wpdb->get_var("SELECT meta_value from wp_postmeta where post_id = $id AND meta_key='_thumbnail_id'");
}

我正在寻找一个优雅的解决方案来解决这个问题。

相关讨论

1	$wpdb = new wpdb( $user, $pass, $db, $host );

创建wpdb对象后，需要设置表名，通过调用set_prefix() method来设置表名。

1	set_prefix( $prefix, $set_table_names = true )

如果你检查你的 sql 错误。表名是空的。默认表前缀是 'wp_'.

解决方案：

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$wpdb = new wpdb( $user, $pass, $db, $host );
$wpdb->set_prefix('wp_');

//then rest of your code..