Конструкция merge в Oracle

MERGE INTO TABLE_NAME 
USING table_reference ON (condition) WHEN MATCHED 
THEN UPDATE SET column1 = value1 [, column2 = value2 ...] WHEN NOT MATCHED 
THEN INSERT (column1 [, column2 ...]) VALUES (value1 [, value2 ...) ;
 

-- удаляем таблички 
drop table person;
drop table person1;
 
-- создаем и заполняем person
create table person(tabn number primary key, name varchar2(#cc66cc;">10), age number);
insert into person values (#cc66cc;">10 , 'Таня', #cc66cc;">22); -- табельный номер , имя , возраст
insert into person values (#cc66cc;">11 , 'Саша', #cc66cc;">9 );
insert into person values (#cc66cc;">12 , 'Вася', #cc66cc;">30);
insert into person values (#cc66cc;">13 , 'Дима', #cc66cc;">39);
insert into person values (#cc66cc;">14 , 'Олег', #cc66cc;">51);
insert into person values (#cc66cc;">15 , 'Витя', #cc66cc;">55);
insert into person values (#cc66cc;">16 , 'Лена', #cc66cc;">67);
insert into person values (#cc66cc;">17 , 'Маня', #cc66cc;">44);
insert into person values (#cc66cc;">18 , 'Даша', #cc66cc;">12);
insert into person values (#cc66cc;">19 , 'Маша', #cc66cc;">24);
insert into person values (#cc66cc;">20 , 'Миша', #cc66cc;">10);
insert into person values (#cc66cc;">21 , 'Миша', #cc66cc;">42);
 
-- создаем person1 на основе person
create table Person1 #b1b100;">as select * from Person;
 
-- изменяем данные в person
UPDATE person SET age = #cc66cc;">55 where tabn in (#cc66cc;">10,#cc66cc;">11,#cc66cc;">12,#cc66cc;">13,#cc66cc;">14,#cc66cc;">15);
delete person where tabn in (#cc66cc;">15,#cc66cc;">18,#cc66cc;">20);
UPDATE person SET age = #cc66cc;">55 where tabn in (#cc66cc;">10,#cc66cc;">11,#cc66cc;">12,#cc66cc;">13,#cc66cc;">14,#cc66cc;">15);
 
-- сливаем таблицы
MERGE INTO person p
   USING (   SELECT tabn, name, age FROM person1) p1
   ON (p.tabn = p1.tabn)
   WHEN MATCHED THEN UPDATE SET p.age = p1.age     
       DELETE WHERE (p.tabn = #cc66cc;">10)
   WHEN NOT MATCHED THEN INSERT (p.tabn, p.name, p.age)
    VALUES (p1.tabn, p1.name, p1.age);
 
-- в person получаем исходные данные, кроме tabn = #cc66cc;">10 его удалили   
select * from person1 p1 left join person p on p.tabn = p1.tabn;