13. A computer program product for interactive data visualization, the computer program product comprising a non-transitory computer readable storage medium having program instructions embodied therewith, the program instructions executable by a computer to cause the computer to perform a method comprising: analyzing, by a hardware processor, a data source used with an initial query submitted by a user to identify a set of default categories available for user selection; dynamically determining, by the hardware processor responsive to a user request directed to at least one of the default categories, pre-set values for categorical portions and numerical portions of vocabularies for user selection using data analytics on the data source; providing, by a user interface, the user with a capability to specify other values for the categorical portions and the numerical portions of the vocabularies; dynamically generating, by the hardware processor, multiple sub-queries to the data source for the values for the categorical portions and numerical portions of the vocabularies, wherein at least one of the multiple sub-queries is dynamically generated for at least one of the other values specified by the user; combining, by the hardware processor, result sets for the multiple sub-queries; and generating, by the hardware processor, a data visualization of the combined result sets and displaying the data visualization on a display device.
13. A computer program product for interactive data visualization, the computer program product comprising a non-transitory computer readable storage medium having program instructions embodied therewith, the program instructions executable by a computer to cause the computer to perform a method comprising: analyzing, by a hardware processor, a data source used with an initial query submitted by a user to identify a set of default categories available for user selection; dynamically determining, by the hardware processor responsive to a user request directed to at least one of the default categories, pre-set values for categorical portions and numerical portions of vocabularies for user selection using data analytics on the data source; providing, by a user interface, the user with a capability to specify other values for the categorical portions and the numerical portions of the vocabularies; dynamically generating, by the hardware processor, multiple sub-queries to the data source for the values for the categorical portions and numerical portions of the vocabularies, wherein at least one of the multiple sub-queries is dynamically generated for at least one of the other values specified by the user; combining, by the hardware processor, result sets for the multiple sub-queries; and generating, by the hardware processor, a data visualization of the combined result sets and displaying the data visualization on a display device. 14. The computer program product of claim 13 , wherein at least one of the multiple sub-queries is out of the data context of the initial query by involving data attributes or vocabulary words uninvolved in the initial query.