I'm able to select pandas dataframe between two dates by first setting a datetime `created` column as index and slicing the dataframe. But now I want to do a new query involving an additional datetime column 'modifieddate' i.e.: 

```
df = df.set_index(['created'])
print (df)
                        name      modifieddate
created                                                        
2014-01-01 16:07:07     john      2014-01-01 16:07:07
2014-01-04 16:07:07     harold    2014-01-04 16:07:07
2014-01-04 16:07:07     clara     2014-01-04 18:07:07
2014-01-05 16:07:07     emily     2014-01-06 16:07:07
2014-01-08 16:07:07     smiths    2014-01-08 16:07:07
2014-01-09 20:07:07     clara     2014-01-09 20:07:07
2014-01-10 18:07:07     clara     2014-01-10 18:07:07
2014-01-10 16:07:07     john      2014-01-11 16:07:07

```

select rows where `created` and `modifieddate` are equal and falls between given datetimes `2014-01-04 16:07:07` and `2014-01-10 16:07:07`:

```
                        name      modifieddate
created                                                        
2014-01-04 16:07:07     harold    2014-01-04 16:07:07 
2014-01-08 16:07:07     smiths    2014-01-08 16:07:07
2014-01-09 20:07:07     clara     2014-01-09 20:07:07

```