在Julia中，我可以使用DataFrames按天或月分组吗

using DataFrames

# 创建一个示例数据框
df = DataFrame(date = [Date(2022, 1, 1), Date(2022, 1, 2), Date(2022, 1, 3), Date(2022, 2, 1), Date(2022, 2, 2)],
               value = [1, 2, 3, 4, 5])

# 按天分组
by_day = by(df, :date, df -> sum(df.value))

# 按月分组
by_month = by(df, :date) do sub_df
    month = Dates.month(first(sub_df.date))
    sum_value = sum(sub_df.value)
    return DataFrame(month = month, sum_value = sum_value)
end