Normalize a Wordpress MySQL table with post meta value

normalize-wordpress-post-fields.php

<?php

/**
 * Return the normalized collection of posts with custom fields
 * @param  string $type  The custom post name
 * @param  array  $infos The list of custom post types required
 * @return array         A collection of post object normalized
 */
function wp_custom_post_normalized_table($type, $infos = []){
    global $wpdb;

    $query = "SELECT ID, post_title as title";
    foreach($infos as $info){
        $query .= ", MAX( CASE WHEN pm.meta_key = '".$info."' THEN pm.meta_value END ) AS ".$info." ";
    }
    $query .= "FROM
            {$wpdb->postmeta} pm LEFT JOIN {$wpdb->posts} p
            ON p.ID = pm.post_id
        WHERE
            ( ";
    foreach($infos as $info){
        $x[] = "pm.meta_key = '".$info."' ";
    }
    $query .= implode(' OR ', $x);
    $query .=")
            AND pm.meta_value IS NOT NULL
            AND p.post_status = 'publish'
            AND p.post_type = '".$type."'
        GROUP BY pm.post_id";

        // return $query;

    $normalized = $wpdb->get_results($query);
	return $normalized;
}