SelectWithUnionQuery (children 1)
 ExpressionList (children 1)
  SelectQuery (children 1)
   ExpressionList (children 1)
    Function CAST (children 1)
     ExpressionList (children 2)
      Function tuple (children 1)
       ExpressionList (children 2)
        Literal \'a\'
        Function array (children 1)
         ExpressionList (children 1)
          Function map (children 1)
           ExpressionList (children 2)
            Literal \'b\'
            Literal \'42\'
      Literal \'Tuple(String, Array(Map(String, FixedString(1000000))))\'
