class ConceptQL::Operators::First

Represents a operator that will grab the first occurrence of something

The operator treats all streams as a single, large stream. It partitions that larget stream by person_id, then sorts within those groupings by start_date and then select at most one row per person, regardless of how many different types of streams enter the operator

If two rows have the same start_date, the order of their ranking is arbitrary

If we ask for the first occurrence of something and a person has no occurrences, this operator returns nothing for that person

Public Instance Methods

occurrence() click to toggle source
# File lib/conceptql/operators/first.rb, line 22
def occurrence
  1
end