fix comparison query timestamp column

[nhsiehgit]

[ceorourke]

Nice, would it be too much to ask to add a test for get_comparison_aggregation_value?

[codecov[bot]]

Codecov Report

All modified and coverable lines are covered by tests :white_check_mark:

Project coverage is 77.86%. Comparing base (2b255d0) to head (80765d4). Report is 73 commits behind head on master.

Additional details and impacted files

@@             Coverage Diff             @@
##           master   #70820       +/-   ##
===========================================
+ Coverage   61.80%   77.86%   +16.05%     
===========================================
  Files        3662     6528     +2866     
  Lines      112673   290944   +178271     
  Branches    18342    50342    +32000     
===========================================
+ Hits        69643   226557   +156914     
- Misses      42651    58132    +15481     
- Partials      379     6255     +5876     

Files	Coverage Δ
src/sentry/search/events/builder/errors.py	97.18% <100.00%> (ø)

... and 2865 files with indirect coverage changes

[volokluev]

This needs a test. If you can't reproduce the issue in a test then how will you know that it was fixed?

[nhsiehgit]

working on the tests now