Execution example::

  select --table Site --limit 0 --drilldown domain --drilldown_output_columns _id,_key,_nsubrecs
  # [
  #   [
  #     0, 
  #     1337566253.89858, 
  #     0.000355720520019531
  #   ], 
  #   [
  #     [
  #       [
  #         9
  #       ], 
  #       [
  #         [
  #           "_id", 
  #           "UInt32"
  #         ], 
  #         [
  #           "_key", 
  #           "ShortText"
  #         ], 
  #         [
  #           "country", 
  #           "SiteCountry"
  #         ], 
  #         [
  #           "domain", 
  #           "SiteDomain"
  #         ], 
  #         [
  #           "link", 
  #           "Site"
  #         ], 
  #         [
  #           "links", 
  #           "Site"
  #         ], 
  #         [
  #           "location", 
  #           "WGS84GeoPoint"
  #         ], 
  #         [
  #           "title", 
  #           "ShortText"
  #         ]
  #       ]
  #     ], 
  #     [
  #       [
  #         3
  #       ], 
  #       [
  #         [
  #           "_id", 
  #           "UInt32"
  #         ], 
  #         [
  #           "_key", 
  #           "ShortText"
  #         ], 
  #         [
  #           "_nsubrecs", 
  #           "Int32"
  #         ]
  #       ], 
  #       [
  #         1, 
  #         ".org", 
  #         3
  #       ], 
  #       [
  #         2, 
  #         ".net", 
  #         3
  #       ], 
  #       [
  #         3, 
  #         ".com", 
  #         3
  #       ]
  #     ]
  #   ]
  # ]