SelectWithUnionQuery (children 1)
 ExpressionList (children 1)
  SelectQuery (children 2)
   ExpressionList (children 2)
    Function CAST (alias x) (children 1)
     ExpressionList (children 2)
      Identifier a
      Literal \'Int32\'
    Function toTypeName (children 1)
     ExpressionList (children 1)
      Identifier x
   TablesInSelectQuery (children 1)
    TablesInSelectQueryElement (children 1)
     TableExpression (children 1)
      Subquery (children 1)
       SelectWithUnionQuery (children 1)
        ExpressionList (children 1)
         SelectQuery (children 1)
          ExpressionList (children 1)
           Function materialize (alias a) (children 1)
            ExpressionList (children 1)
             Function CAST (children 1)
              ExpressionList (children 2)
               Literal UInt64_42
               Literal \'Nullable(UInt8)\'