EDD\HelpScout\Endpoint::query_customer_payments PHP Method

    private function query_customer_payments()
    {
        $payments = array();
        /**
         * Allows you to perform your own search for customer payments, based on given data.
         *
         * @since 1.1
         */
        $payments = apply_filters('edd_helpscout_customer_payments', $payments, $this->customer_emails, $this->data);
        if (!empty($payments)) {
            return $payments;
        }
        global $wpdb;
        // query by email(s)
        $sql = "SELECT p.ID, p.post_status, p.post_date";
        $sql .= " FROM {$wpdb->posts} p, {$wpdb->postmeta} pm";
        $sql .= " WHERE p.post_type = 'edd_payment'";
        $sql .= " AND p.ID = pm.post_id";
        $sql .= " AND pm.meta_key = '_edd_payment_user_email'";
        if (count($this->customer_emails) > 1) {
            $in_clause = rtrim(str_repeat("'%s', ", count($this->customer_emails)), ", ");
            $sql .= " AND pm.meta_value IN({$in_clause})";
        } else {
            $sql .= " AND pm.meta_value = '%s'";
        }
        $sql .= " GROUP BY p.ID  ORDER BY p.ID DESC";
        $query = $wpdb->prepare($sql, $this->customer_emails);
        $results = $wpdb->get_results($query);
        if (is_array($results)) {
            return $results;
        }
        return array();
    }