SelectWithUnionQuery (children 1)
 ExpressionList (children 1)
  SelectQuery (children 2)
   ExpressionList (children 1)
    Function argMaxOrNull (children 1)
     ExpressionList (children 2)
      Identifier id
      Identifier timestamp
   TablesInSelectQuery (children 1)
    TablesInSelectQueryElement (children 1)
     TableExpression (children 1)
      Subquery (children 1)
       SelectWithUnionQuery (children 1)
        ExpressionList (children 1)
         SelectQuery (children 1)
          ExpressionList (children 2)
           Function CAST (alias id) (children 1)
            ExpressionList (children 2)
             Literal NULL
             Literal \'Nullable(UInt32)\'
           Literal UInt64_2 (alias timestamp)
