title: ValueError: You are trying to merge on object and int64 columns when use pandas merge
body: <p>The test.csv data likes this:</p>
  <pre><code>device_id,upload_time,latitude,longitude,mileage,other_vals,speed,upload_time_1
  11115304371,2020-08-05 05:10:05+00:00,23.140366,114.18685,0,,0,202008
  1234,2020-08-05 05:10:33+00:00,22.994716,114.2998,0,,0,202008
  11115304371,2020-08-05 05:20:55+00:00,22.994716,114.2998,0,,3.8,202008
  11115304371,2020-08-05 05:24:02+00:00,22.994916,114.299683,0,,2.1,202008
  11115304371,2020-08-05 05:24:30+00:00,22.99545,114.2998,0,,6.5,202008
  11115304371,2020-08-05 05:29:30+00:00,22.995433,114.299766,0,,3.4,202008
  11115304371,2020-08-05 05:34:30+00:00,22.995433,114.299766,0,,3.4,202008
  11115304371,2020-08-05 05:39:30+00:00,22.995433,114.299766,0,,3.4,202008
  822649e2d142a486,2020-08-05 05:44:30+00:00,22.995433,114.299766,0,,3.4,202008
  11115304371,2020-08-05 05:44:53+00:00,22.995433,114.299766,0,,3.4,202008
  11115304371,2020-08-05 05:45:40+00:00,22.995433,114.299766,0,,5.8,202008
  </code></pre>
  <p>And the info.csv data likes this:</p>
  <pre><code>car_id,device_id,car_type,car_num,marketer_name
  1,11110110037,1,AAA,T1
  2,11115304371,1,BBB,T2
  3,11111100345,1,CCC,T3
  4,11111100242,1,DDD,T4
  5,12221100034,1,EEE,T5
  6,12221100230,1,FFF,T6
  7,14465301234,1,GGG,T7
  </code></pre>
  <p>When I use this code to merge 2 dataframe.</p>
  <pre><code>import pandas as pd
  
  df_device_data = pd.read_csv(r'E:/test.csv', encoding='utf-8', parse_dates=[1], low_memory=False)
  df_common_car_info = pd.read_csv(r'E:/info.csv', encoding='utf-8', low_memory=False)
  result = pd.merge(df_device_data, df_common_car_info, how='left', on='device_id')
  result.to_csv(r'E:/result.csv', index=False, mode='w', header=True)
  </code></pre>
  <p>This error occurred:</p>
  <blockquote>
  <p>ValueError: You are trying to merge on object and int64 columns. If
  you wish to proceed you should use pd.concat</p>
  </blockquote>
  <p>How to fix it?</p>