我的查询在wordpress中返回null，我不知道为什么

Question

What's wrong with this query? It always returns NULL.

$recipes = $wpdb->get_results(
       "SELECT ID FROM ".$wpdb->posts." WHERE post_author = %d AND post_status IN ('draft','publish') AND post_type = 'recipes' ", $current_user->ID
        );

Answer 1

get_results takes output type as second parameter. You're missing prepare method if you want to do it like this. It should be something like

 $recipes = $wpdb->get_results($wpdb->prepare ("SELECT ID FROM ".$wpdb->posts." 
 WHERE post_author = %d 
 AND post_status IN ('draft','publish') 
 AND post_type = 'recipes' ", $current_user->ID));