text: --[er]test (/) operator using set data type divide(/) multiset data type
  
  create class func_02 ( a set of int, b multiset of int , c list of int );
  insert into func_02 values ( {},{},{});
  insert into func_02 values ( null,null,null);
  insert into func_02 values ( {1,1},{2,2},{3,3});
  insert into func_02 values ( {1,2,3},{1,2,3},{1,2,3});
  insert into func_02 values ( {-1,-2,-3},{-1,-2,-3},{-1,-2,-3});
  
  select a / b / c from func_02 order by 1;
  
  drop  class func_02;
  