SelectWithUnionQuery (children 1)
 ExpressionList (children 1)
  SelectQuery (children 1)
   ExpressionList (children 1)
    Literal \'R1, R2, R3 + additional_table_filters and WHERE: (x == 1) OR (x == 2) OR (x == 3) AND (x < 3) AND (x > 1)\'