[examples] let's not use 'date' as a col name

[mistercrunch]

'date' is a reserved word in most database

[codecov-io]

Codecov Report

Merging #4555 into master will not change coverage.
The diff coverage is 100%.

@@           Coverage Diff           @@
##           master    #4555   +/-   ##
=======================================
  Coverage   71.12%   71.12%           
=======================================
  Files         187      187           
  Lines       14780    14780           
  Branches     1083     1083           
=======================================
  Hits        10513    10513           
  Misses       4264     4264           
  Partials        3        3

Impacted Files	Coverage Δ
superset/data/__init__.py	100% <100%> (ø)	⬆️

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[betodealmeida]

LGTM, but I think this is a somewhat good way of testing if column names are properly escaped by the SQLAlchemy connector. Did this cause any problems?

[mistercrunch]

I agree about having it as a way to improve the tests and prevent regressions, though my immediate urge was to fix the examples that were broken in MySQL.

In that spirit we do have a unicode-filled dataset in there, we should probably add a new dataset with reserved words as columns, table names and unicode-ridden column names and such.

Let's fix the examples for now and open an issue to address unicode and reserved words support as a task.