How to change a custom query into a standard loop?

Question

I'm trying to modify how results are displayed in a post list that's currently controlled by the code below. However, it's not built in the WP_Query while ( $the_query->have_posts() ) : $the_query->the_post(); style I'm accustomed to and have built a lot of shortcodes and loop styles around.

How can I change the code below into a "regular" Wordpress loop that will allow me to use template tags like the_title()?

    $totalposts = $wpdb->get_results($querystr, OBJECT);
    $wp_query->request = $querystr . " LIMIT " . $ppp . " OFFSET " .$offset;
    $results = $wpdb->get_results($wp_query->request, OBJECT);
    foreach ($results as $result) {
        $offset++;
        $output .= '<a href="'.get_post_permalink($result->ID).'">' . $result->post_title . ' (' . $result->post_date . ')</a><br>';
    }

Answer 1

How I have done custom queries in the past is use $wpdb->get_col() and just returned an array of IDs of the posts. Then I pass that to a get_posts() passing the IDs to the post__in parameter. That way you can then use WP standard controls.

Answer 2

In order to be able to use template tags, you have to do two things after getting your custom select query:

1. You have to declare the global $post variable.
2. You have to call the setup_postdata($post) function to populate the variables.

So, my code had to be changed like so:

$results = $wpdb->get_results($wp_query->request, OBJECT);
global $post;
foreach ($results as $post) {
    setup_postdata($post); 
?>
<h4><a href="<?php the_permalink(); ?>"><?php the_title(); ?></a></h4>

etc.

The key to this is on this codex page:

Displaying posts using a custom select query