SelectWithUnionQuery (children 1)
 ExpressionList (children 1)
  SelectQuery (children 1)
   ExpressionList (children 1)
    Function toTypeName (children 1)
     ExpressionList (children 1)
      Function randCanonical (children 1)
       ExpressionList (children 1)
        Function CAST (children 1)
         ExpressionList (children 2)
          Literal UInt64_4
          Literal \'Nullable(UInt8)\'