Code used to create SQL clauses for meta queries using custom tables (Draft)

custom-meta-query.php

<?php

$regions_query = new WP_Meta_Query( $query_object->query['_regions_query'] );
$regions_clauses = $regions_query->get_sql( 'post', $this->db->posts, 'ID', $query_object );

$regions_clauses['join'] = str_replace( $this->db->postmeta, AWPCP_TABLE_AD_REGIONS, $regions_clauses['join'] );
$regions_clauses['join'] = preg_replace( "/mt(\d+)/", 'listing_regions\1', $regions_clauses['join'] );
$regions_clauses['join'] = str_replace( 'post_id', 'ad_id', $regions_clauses['join'] );

$regions_clauses['where'] = str_replace( $this->db->postmeta, AWPCP_TABLE_AD_REGIONS, $regions_clauses['where'] );
$regions_clauses['where'] = preg_replace( "/mt(\d+)/", 'listing_regions\1', $regions_clauses['where'] );
$regions_clauses['where'] = preg_replace(
    "/(\w+).meta_key = '(\w+)' AND CAST\([^)]+\) (LIKE '(?:\\\'|[^'])+')/",
    '$1.$2 $3',
    $regions_clauses['where'],
    -1,
    $count
);

$clauses['join'] = $clauses['join'] . $regions_clauses['join'];
$clauses['where'] = $clauses['where'] . $regions_clauses['where'];