ENH: DataFrame.query() should prioritize column names over types defined in local scope.

[chrisjcameron]

Is your feature request related to a problem?

If a column name matches a defined type it does not seem to be possible to include the column in a .query() string. For instance, df.query("Timestamp < 10") throws a TypeError: '<' not supported between instances of 'type' and 'int' for a dataframe where df[df.Timestamp < 10] yields the expected result.

Describe the solution you'd like

Ideally, a query string should prioritize the the column or row index values for the dataframe whose .query method is called. This the natural scope of a query on a dataframe and we already have special operators (e.g. @) to indicate that objects that exist outside the dataframe "namespace". The current behavior to automatically search outside the dataframe is almost a bug.

Describe alternatives you've considered

Alternative 1: Perhaps the backtick escaping for column names with spaces could be extended to prefer matching dataframe column names over classes in the local scope. It does not make as much sense namespace-wise but it is less breaking than the proposed solution.