A system for multicolumn ordering includes a processor and a data store.
The data store stores a table including a plurality of category and data
columns. The processor applies key prefixes to column data values of a
plurality of the data columns to form and store in the data store a set
of prefixed data values. The processor then orders the set of prefixed
data values in a first compound column and one or more category columns
in a second compound column and responsive to the first and second
compound columns selects and stores a subset for further processing.