Filters

// Filter by Rating
add_action( 'restrict_manage_posts', 'bpl_admin_posts_filter_restrict_reviews_by_rating' );
function bpl_admin_posts_filter_restrict_reviews_by_rating(){
    $type = 'customer_reviews';
    if (isset($_GET['post_type'])) { $type = $_GET['post_type']; }

    //only add filter to post type you want
    if ('customer_reviews' == $type){
        //change this to the list of values you want to show
        //in 'label' => 'value' format
        $r_values = array(
            '5 Star Reviews' => '5',
            '4 Star Reviews' => '4',
            '3 Star Reviews' => '3',
            '2 Star Reviews' => '2',
            '1 Star Reviews' => '1',
        );
        echo "<select name=\"bpl_rating_value\"><option value=\"\">Rating</option>";
        $current_v = isset($_GET['bpl_rating_value'])? $_GET['bpl_rating_value']:'';
        foreach ($r_values as $label => $value) {
            printf (
                '<option value="%s"%s>%s</option>',
                $value,
                $value == $current_v? ' selected="selected"':'',
                $label
            );
        }
        echo "</select>";
    }
}

add_filter( 'parse_query', 'bpl_posts_filter_reviews_by_rating' );
function bpl_posts_filter_reviews_by_rating( $query ){
    global $pagenow;
    $type = 'customer_reviews';
    if (isset($_GET['post_type'])) { $type = $_GET['post_type']; }

    if ( 'customer_reviews' == $type && is_admin() && $pagenow=='edit.php' && isset($_GET['bpl_rating_value']) && $_GET['bpl_rating_value'] != '') {
        $query->query_vars['meta_key'] = 'cust_rating';
        $query->query_vars['meta_value'] = $_GET['bpl_rating_value'];
    }
}

// Filter by Technician
add_action('restrict_manage_posts','restrict_bpl_reviews_by_tech');
function restrict_bpl_reviews_by_tech() {
    global $wpdb;
    $type = 'customer_reviews';
    if (isset($_GET['post_type'])) { $type = $_GET['post_type']; }

    if ('customer_reviews' == $type){
        $techs = $wpdb->get_col("SELECT DISTINCT meta_value FROM ". $wpdb->postmeta ." WHERE meta_key = 'customer_tech' ORDER BY meta_value");
        echo "<select name=\"bpl_restrict_reviews_by_tech\" id=\"review_techs\"><option value=\"\">Technician</option>";
        foreach ($techs as $tech) :
            $the_value = unserialize( $tech );
            echo "<option value=\"",$the_value[0],"\">";
            if ( isset ($_GET['bpl_restrict_reviews_by_tech']) && !empty($_GET['bpl_restrict_reviews_by_tech']) ) { selected($_GET['bpl_restrict_reviews_by_tech'], $tech); }
            $tech = get_post($tech);
            echo get_the_title($the_value[0]);
            echo "</option>";
        endforeach;
        echo "</select>";
    }
}

add_filter( 'parse_query', 'bpl_posts_filter_reviews_by_tech' );
function bpl_posts_filter_reviews_by_tech( $where ){
    global $pagenow;
    $type = 'customer_reviews';
    if (isset($_GET['post_type'])) { $type = $_GET['post_type']; }

    if ( 'customer_reviews' == $type && is_admin() && $pagenow=='edit.php' && isset($_GET['bpl_restrict_reviews_by_tech']) && $_GET['bpl_restrict_reviews_by_tech'] != '') {
        $where->query_vars['meta_key'] = 'customer_tech';
        $where->query_vars['meta_value'] = $_GET['bpl_restrict_reviews_by_tech'];
    }
}