无法从SQL执行中正确获取ResultSet

我有一些我用Tasks为学校创建的数据库。每个Task记录都有用户名、描述、taskday和taskhour列。

我想通过两个值来提取记录:taskhour和taskday,或者分别提取。

因此,我有一个函数,它获取一个任务对象,检查taskday或taskhour是否为空,并相应地准备查询。但由于某种原因,ResultSet出现了问题……这是我的函数:

public List<Task> getUserTasks(Task task) throws SQLException {

    List<Task> listOfTasks = new ArrayList<>();

    try {

         String query = "";
         PreparedStatement pStatement;

        if (task.getDay() != 0 && task.getHour() != 0) {
            query = "select * from TASKS where USERNAME=? and TASKDAY=? and TASKHOUR=?";
            pStatement = connection.prepareStatement(query);
            pStatement.setString(1, task.getUsername());
            pStatement.setInt(2, task.getDay());
            pStatement.setInt(3, task.getHour());

        } else if (task.getDay() == 0) {
            query = "select * from TASKS where USERNAME=? and TASKHOUR=?";
            pStatement = connection.prepareStatement(query);
            pStatement.setString(1, task.getUsername());
            pStatement.setInt(2, task.getHour());

        } else {
            query = "select * from TASKS where USERNAME=? and TASKDAY=?";
            pStatement = connection.prepareStatement(query);
            pStatement.setString(1, task.getUsername());
            pStatement.setInt(2, task.getDay());
        }


        ResultSet rs;
        rs = pStatement.executeQuery();

        if (rs.next()) {
            Task taskToAdd = new Task();

            taskToAdd.setUsername(rs.getString("USERNAME"));
            taskToAdd.setDescription(rs.getString("DESCRIPTION"));
            taskToAdd.setDay(rs.getInt("TASKDAY"));
            taskToAdd.setHour(rs.getInt("TASKHOUR"));

            listOfTasks.add(taskToAdd);
        }

    } catch (SQLException ex) {
        ex.printStackTrace();
    }

    return listOfTasks;      
}   

我做错什么了吗?

谢谢