wpdb custom post_type problem

I want to use custom post type in my custom SQL query, but, when I add the custom post type im my query, I get no results.

Where’s my probelm ?

This is the code I’ve tried

$top5_ov_performance = $wpdb->get_results("SELECT post_id,meta_value FROM ".$wpdb->prefix."postmeta WHERE meta_key = 'sd_top5_overclocing' AND (post_type = 'cpu')  ORDER BY meta_value DESC LIMIT 0,5 ");

I have also tried this post_type = 'cpu' instead of (post_type = 'cpu') and and instead of AND

Solutions Collecting From Web of "wpdb custom post_type problem"

If you’re trying to get all meta values for a key within a specific post type, you can do something like this in a single query:

SELECT post_id, meta_value FROM $wpdb->postmeta pm, $wpdb->posts p
WHERE meta_key = 'sd_rating' and pm.post_id = p.ID  AND p.post_type = 'cpu'

I have found a way :

global $wpdb,$post;
                                    $query_ids = $wpdb->get_results("SELECT ID FROM ".$wpdb->prefix."posts WHERE (post_type = 'cpu') LIMIT 0,10");
                                        foreach ($query_ids as $query_id) {
                                            $query = $wpdb->get_results("SELECT * FROM ".$wpdb->prefix."postmeta WHERE post_id = ".$query_id->ID." AND meta_key = 'sd_rating' ORDER BY meta_value LIMIT 0,10");
                                                foreach ($query as $value) {
                                                    echo $value->meta_value;