SelectWithUnionQuery (children 1)
 ExpressionList (children 1)
  SelectQuery (children 1)
   ExpressionList (children 1)
    Function arrayUnion (children 1)
     ExpressionList (children 2)
      Literal Array_[UInt64_1]
      Function array (children 1)
       ExpressionList (children 1)
        Function CAST (children 1)
         ExpressionList (children 2)
          Literal \'a\'
          Literal \'Dynamic\'
