Add minimal support for querying multiple catalogs

[AlexandreOuellet]

This adds the catalog names in front of fields and table when needed. It will most likely require more finetuning but is a working prototype

[VinceDPM]

We're interested in this feature being integrated into a future release of PyHive. Is there any reason (besides failed travis CI) that the PR was never approved?

[AlexandreOuellet]

To be honest, I made this for work, created the PR and forgot about it. I can have a quick look to make it pass the flake8 issues

[codecov[bot]]

Codecov Report

Merging #246 into master will decrease coverage by 1.48%. The diff coverage is n/a.

@@            Coverage Diff             @@
##           master     #246      +/-   ##
==========================================
- Coverage   93.94%   92.46%   -1.49%     
==========================================
  Files          14       14              
  Lines        1487     1553      +66     
  Branches      159      170      +11     
==========================================
+ Hits         1397     1436      +39     
- Misses         64       84      +20     
- Partials       26       33       +7     

Impacted Files	Coverage Δ
pyhive/presto.py	83.43% <0.00%> (-10.19%)	:arrow_down:
pyhive/sqlalchemy_hive.py	86.44% <0.00%> (ø)	:arrow_up:
pyhive/tests/test_presto.py	100.00% <0.00%> (ø)	:arrow_up:
pyhive/tests/sqlalchemy_test_case.py	100.00% <0.00%> (ø)	:arrow_up:

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[AlexandreOuellet]

This is as far as I can get tonight. It's alright with python 3.6, but fails with 3.5, 3.4 and 2.7. Feel free to fork off of my branch if you want to contribute to it.

[VinceDPM]

Thanks, I found a similar str bug and made a PR against your branch that fixes the build for python 3.4/5, and added fix for python 2.7 syntax.

[cerodav]

Hi Could you give an example on how to create the engine and query multiple catalgoues ?

[laserkaplan]

I noticed that this repo currently says it's unsupported, but is there any way we would be able to get this PR merged and into another release? I also now have the need for the functionality here. Happy to help implement whatever tests are required to get this through.

[CLAassistant]

Thank you for your submission! We really appreciate it. Like many open source projects, we ask that you all sign our Contributor License Agreement before we can accept your contribution.
2 out of 3 committers have signed the CLA.

:white_check_mark: VinceDPM
:white_check_mark: AlexandreOuellet
:x: Aleandre Ouellet

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