如何使用datetime索引连接两个数据帧，同时只保留同一时间段的数据？

import pandas as pd

df1 = pd.DataFrame({'datetime': ['2022-01-01 10:00:00', '2022-01-01 11:00:00', '2022-01-01 12:00:00'],
                    'data1': [1, 2, 3]})
df2 = pd.DataFrame({'datetime': ['2022-01-01 10:00:00', '2022-01-01 11:00:00', '2022-01-01 12:00:00'],
                    'data2': [4, 5, 6]})

df1['datetime'] = pd.to_datetime(df1['datetime'])
df1.set_index('datetime', inplace=True)

df2['datetime'] = pd.to_datetime(df2['datetime'])
df2.set_index('datetime', inplace=True)

df_merged = df1.join(df2, how='inner')

print(df_merged)

import pandas as pd

df1 = pd.DataFrame({'datetime': ['2022-01-01 10:00:00', '2022-01-01 11:00:00', '2022-01-01 12:00:00'],
                    'data1': [1, 2, 3]})
df2 = pd.DataFrame({'datetime': ['2022-01-01 10:00:00', '2022-01-01 11:00:00', '2022-01-01 12:00:00'],
                    'data2': [4, 5, 6]})

df1['datetime'] = pd.to_datetime(df1['datetime'])
df1.set_index('datetime', inplace=True)

df2['datetime'] = pd.to_datetime(df2['datetime'])
df2.set_index('datetime', inplace=True)

df_merged = df1.join(df2, how='inner')

print(df_merged)