web-and-algorithms-ubuntu: cannot build histograms for sample data as wrong groupings are used

[ludovicc]

python-hystogram fails with:

WARNING:root:Cannot execute the following query on the input DB: select score_math_course2,dataset,gender,agegroup,alzheimerbroadcategory from sample_data where score_math_course2 is not null and dataset is not null and gender is not null and agegroup is not null and alzheimerbroadcategory is not null

Expected solution: configurable definition of groupings instead of pre-defined groups 'dataset,gender,agegroup,alzheimerbroadcategory'