如何使用php / pdo从MySQL数据库中删除友谊并检查它是否成功

Im trying to delete a friendship between two users from the db

the friendship table is simple:

friend_one |friend_two
100        |142
142        |100

Here is the code I have, but its not working:

if (!empty($_POST)) {

    $remover_id      = $_POST['remover_id'];
    $removed_id      = $_POST['removed_id'];

    try {

        $query = "DELETE * FROM 

                 `friendships` 

                 WHERE 

                 (friend_one = :remover_id AND friend_two = :removed_id)

                 OR 

                 (friend_two = :remover_id AND friend_one = :removed_id)

                 ";

        $sth = $connection->prepare($query);

        $sth->execute(
                      array(

                            ':remover_id' => $remover_id,
                            ':removed_id' => $removed_id

                            ));   

        if($sth->rowCount () >=0){
            $response["success"] = $http_response_success;
            die(json_encode($response));
            $connection = null; 
        } else {
            $response["success"] = $http_response_server_error;
            $response["message"] = $http_message_server_error;   
            die(json_encode($response));
            $connection = null;
        }

    } catch (PDOException $ex) {

        $response["success"] = $http_response_server_error;
        $response["message"] = $http_message_server_error;
        die(json_encode($response));
        $connection = null;

    }  


} else {
        $response["success"] = $http_response_bad_request;
        $response["message"] = $http_message_bad_request;   
        die(json_encode($response));
        $connection = null;
}

First of all I dont think the way I check for success is correct, second of all, the friendship doesnt get removed from the DB anyway.

When I run this I find myself in the else statement:

    if($sth->rowCount () >=0){
        $response["success"] = $http_response_success;
        die(json_encode($response));
        $connection = null; 
    } else {
        $response["success"] = $http_response_server_error;
        $response["message"] = $http_message_server_error;   
        die(json_encode($response));
        $connection = null;
    }