UNION keyword

The keyword can be written in capital or small letters, but not mixed.

The keyword requires a list of parameters (at least one), where each parameter defines a collection for building the union. The operation unites the calling collection with a list of passed collections. When being used without calling collection, the operation unites all passed collections.

Calling Union like

A.Union(B)

Unites A with B and stores the result in A. Calling Union, however, as

Union(A,B)

Creates a new collection containing the union of A and B.