Select two value from meta key and post meta

Question

I want to ask best method to select two meta value from same column

my code

global $wpdb, $bp;
            $user_id            =   get_current_user_id();
            $vlues=$wpdb->get_results(sprintf("
            SELECT rel.post_id as id, rel.meta_value as val
                FROM {$wpdb->posts} AS posts
                LEFT JOIN {$wpdb->postmeta} AS rel ON posts.ID = rel.post_id
                WHERE   posts.post_type   = 'books'
                AND     posts.post_title LIKE '%%fire'
                AND     posts.post_status   = 'publish'

                // Select specific book id
                AND     rel.meta_key   = 'books_id'
                AND     rel.meta_value = '1351'

                // Check complete book
                AND     rel.meta_key   = %d
                AND     rel.meta_value > 0
                ", $user_id)
            );

Answer 1

You just need to join postmeta twice:

global $wpdb, $bp;

$user_id = get_current_user_id();

$query = $wpdb->prepare(
    "SELECT 
        rel.post_id as id, 
        rel2.meta_value as val
    FROM {$wpdb->posts} AS posts
        LEFT JOIN {$wpdb->postmeta} AS rel ON 
            posts.ID = rel.post_id
        LEFT JOIN {$wpdb->postmeta} AS rel2 ON
            posts.ID = rel2.post_id
    WHERE
        posts.post_type = 'books' AND
        posts.post_title LIKE '%%fire' AND
        posts.post_status = 'publish' AND 
        rel.meta_key = 'books_id' AND
        rel.meta_value = '1351' AND
        rel2.meta_key = %d AND
        rel2.meta_value > 0",
    $user_id
);

$values = $wpdb->get_results( $query );

Also note that I used $wpdb->prepare() in place of sprintf(). It's the preferred method for safely putting values into a query with WordPress.