create table myTab (pid numeric, sales numeric, status varchar(6));
create table myTab2 (pid numeric, sales numeric, status varchar(6));
truncate table myTab;
truncate table myTab2;
insert into myTab2 values(1,12,'CURR');
insert into myTab2 values(2,13,'NEW' );
insert into myTab2 values(3,15,'CURR');
insert into myTab  values(2,24,'CURR');
insert into myTab  values(3, 0,'OBS' );
insert into myTab  values(4,42,'CURR');

WITH 
del as(
        delete from mytab2 m2
        using mytab m
        where m2.pid=m.pid and m2.sales<m.sales
        RETURNING m2.*
),
upd as (
   update mytab2 m 
   set sales=m.sales+d.sales, 
       status=d.status 
   from del d 
   where m.pid=d.pid
   RETURNING m.*
),
ins as (
    select pid, 
           sales,
           'NEW' 
    from mytab
    where pid not in (select pid from mytab2)
)
insert into mytab2
    select *
    from ins;
select * from myTab2;

pid	sales	status
1	12	CURR
2	13	NEW
3	15	CURR

pid	sales	status
pid	sales	status
1	12	CURR
3	15	CURR
4	42	NEW

WITH 
del as(
        delete from mytab2 m2
        using mytab m
        where m2.pid=m.pid and m2.sales<m.sales
        RETURNING m2.*
),
upd as (
   update mytab2 m2 
   set sales=m2.sales+m.sales, 
       status=m.status 
   from mytab m--, del d 
   where m2.pid=m.pid and m2.pid not in (select pid from del)
   RETURNING m2.*
),
ins as (
    select pid, 
           sales,
           'NEW' 
    from mytab
    where pid not in (select pid from mytab2) and pid not in (select pid from upd)
)
insert into mytab2
    select *
    from ins;

pid	sales	status
1	12	CURR
3	16	OBS
4	42	NEW