如何在Wordpress文件中编写select语句，如“；function.php”； - How to write a select statement in Wordpress file like "function.php"

How to write a select statement in Wordpress file like "function.php"

我以前在phpmyadmin中尝试过这段代码，它在中运行良好

SELECT meta_value
FROM wp_postmeta
INNER JOIN wp_posts ON post_id =564
WHERE meta_key =  'max_person';

但我不知道如何将其插入函数.php

我插入这个代码，它工作

<? PHP 
    $postid = get_the_ID();
    $maxperson = $wpdb->get_row( $wpdb->prepare(
    "SELECT meta_value FROM wp_postmeta inner join wp_posts ON post_id= %d WHERE meta_key = 'max_person'", $postid
        ) );
?>

但当我var_dumped $maxperson var_dump ($maxperson);时，它返回

object(stdClass)#634 (1) { ["meta_value"]=> string(1) "5" }结果应该是"5"我不明白这意味着什么

您必须使用自定义查询来获取逐帖ID或任何其他属性。详细信息请参阅WP文档。http://codex.wordpress.org/Class_Reference/WP_Query

$args = array(
'p' => 42, // id of post
'meta_key' => 'max_person');
$my_posts = new WP_Query($args);

我得到了

$value = (integer) $maxperson->meta_value;