Added tests for queries 17 and 19. Currently not passing.
Added tests for queries 17 and 19. Currently not passing.


Former-commit-id: 541bb56a8c1ee28e86e31ad66e7be6984caa0ab9
HPI-SWA-Lab/SQPyte,HPI-SWA-Lab/SQPyte,HPI-SWA-Lab/SQPyte,HPI-SWA-Lab/SQPyte,HPI-SWA-Lab/SQPyte