Aggregate functions

EQL provides three aggregators for working with sets.

The set aggregate functions can be used only in SELECT clauses.

• SET function
  The SET aggregation function takes a single-assign attribute and constructs a set of all of the (non-NULL) values from that attribute.
• SET_INTERSECTIONS function
  The SET_INTERSECTIONS aggregation function takes a multi-assign attribute and constructs a set that is the intersection of all of the values from that attribute.
• SET_UNIONS function
  The SET_UNIONS aggregation function takes a multi-assign attribute and constructs a set that is the union of all of the values from that attribute.