helper.py 文件源码

def calculate_avg(user_id, start_date, end_date, column_name):
    """Calculates average of field with column_name from start_date to end_date."""

    avg = db.session.query(func.avg(column_name)).filter\
                        (Entry.user_id == user_id, Entry.date >= start_date, \
                            Entry.date <= end_date)
    avg = avg[0][0]
    return avg