SelectWithUnionQuery (children 1)
 ExpressionList (children 1)
  SelectQuery (children 2)
   ExpressionList (children 2)
    Function sum (children 1)
     ExpressionList (children 1)
      Function length (children 1)
       ExpressionList (children 1)
        Identifier nested.arr1
    Function sum (children 1)
     ExpressionList (children 1)
      Function length (children 1)
       ExpressionList (children 1)
        Identifier nested.arr2
   TablesInSelectQuery (children 1)
    TablesInSelectQueryElement (children 1)
     TableExpression (children 1)
      TableIdentifier t_update_empty_nested
