BUG: The query method does not support index or column named datetime

[esse-byte]

In [1]: import pandas as pd
In [2]: index = pd.MultiIndex.from_product([['T0', 'T1'], ['A', 'B']], names=['datetime', 'count'])
In [3]: frame = pd.DataFrame({'isnull': range(len(index))}, index=index)
In [4]: frame.query('count == "A"') # works
Out[4]: 
                isnull
datetime count        
T0       A           0
T1       A           2

In [5]: frame.query('isnull < 2') # works
Out[5]: 
                isnull
datetime count        
T0       A           0
         B           1

In [6]: frame.query('datetime == "T0"') # failed caused by KeyError
---------------------------------------------------------------------------
KeyError                                  Traceback (most recent call last)
D:\home\tools\Anaconda\lib\site-packages\pandas\core\indexes\base.py in get_loc(self, key, method, tolerance)
   2645             try:
-> 2646                 return self._engine.get_loc(key)
   2647             except KeyError:

...

D:\home\tools\Anaconda\lib\site-packages\pandas\core\indexes\base.py in get_loc(self, key, method, tolerance)
   2646                 return self._engine.get_loc(key)
   2647             except KeyError:
-> 2648                 return self._engine.get_loc(self._maybe_cast_indexer(key))
   2649         indexer = self.get_indexer([key], method=method, tolerance=tolerance)
   2650         if indexer.ndim > 1 or indexer.size > 1:

pandas\_libs\index.pyx in pandas._libs.index.IndexEngine.get_loc()
pandas\_libs\index.pyx in pandas._libs.index.IndexEngine.get_loc()
pandas\_libs\hashtable_class_helper.pxi in pandas._libs.hashtable.PyObjectHashTable.get_item()
pandas\_libs\hashtable_class_helper.pxi in pandas._libs.hashtable.PyObjectHashTable.get_item()
KeyError: False

In [7]: index2 = pd.MultiIndex.from_product([pd.date_range('20200101', '20200202'), ['A', 'B']], names=['datetime', 'count'])
In [8]: frame2 = pd.DataFrame({'isnull': range(len(index2))}, index=index2)
In [9]: frame2.query('datetime == "2020-01-01"') # failed caused by TypeError
---------------------------------------------------------------------------
KeyError                                  Traceback (most recent call last)
D:\home\tools\Anaconda\lib\site-packages\pandas\core\indexes\base.py in get_loc(self, key, method, tolerance)
   2645             try:
-> 2646                 return self._engine.get_loc(key)
   2647             except KeyError:

...

D:\home\tools\Anaconda\lib\site-packages\pandas\core\indexes\datetimes.py in get_loc(self, key, method, tolerance)
    721 
    722             try:
--> 723                 stamp = Timestamp(key)
    724                 if stamp.tzinfo is not None and self.tz is not None:
    725                     stamp = stamp.tz_convert(self.tz)

pandas\_libs\tslibs\timestamps.pyx in pandas._libs.tslibs.timestamps.Timestamp.__new__()
pandas\_libs\tslibs\conversion.pyx in pandas._libs.tslibs.conversion.convert_to_tsobject()
TypeError: Cannot convert input [False] of type <class 'numpy.bool_'> to Timestamp

Problem description

The query method failed when the query expression contains datetime.

Expected Output

Output of pd.show_versions()

INSTALLED VERSIONS

commit : None
python : 3.8.3.final.0
python-bits : 64
OS : Windows
OS-release : 10
machine : AMD64
processor : Intel64 Family 6 Model 158 Stepping 10, GenuineIntel
byteorder : little
LC_ALL : None
LANG : None
LOCALE : Chinese (Simplified)_China.936

pandas : 1.0.5
numpy : 1.18.5
pytz : 2020.1
dateutil : 2.8.1
pip : 20.1.1
setuptools : 49.2.0.post20200714
Cython : None
pytest : None
hypothesis : None
sphinx : 3.1.2
blosc : None
feather : None
xlsxwriter : None
lxml.etree : None
html5lib : None
pymysql : None
psycopg2 : None
jinja2 : 2.11.2
IPython : 7.16.1
pandas_datareader: None
bs4 : None
bottleneck : None
fastparquet : None
gcsfs : None
lxml.etree : None
matplotlib : 3.2.2
numexpr : 2.7.1
odfpy : None
openpyxl : None
pandas_gbq : None
pyarrow : None
pytables : None
pytest : None
pyxlsb : None
s3fs : None
scipy : 1.5.0
sqlalchemy : None
tables : 3.6.1
tabulate : 0.8.3
xarray : None
xlrd : 1.2.0
xlwt : None
xlsxwriter : None
numba : 0.50.1

[samukweku]

Does it work if you set the engine argument to python?

[esse-byte]

Does it work if you set the engine argument to python?

It does not work either

[samukweku]

I suspect it is confusing it with the datetime module name from python; if you use a different name it works, if you try to access it using frame[frame.index.get_level_values("datetime") == "T0"] it works. That's my guess