Puoi usare il LAG() funzione finestra per dare un'occhiata alla riga precedente e confrontarla. Se i tuoi dati sono:
create table t2 (
id number(6),
cctr varchar2(10),
date1 date
);
insert into t2 (id, cctr, date1) values (1, '2C', date '2018-08-01');
insert into t2 (id, cctr, date1) values (2, '2C', date '2018-07-02');
insert into t2 (id, cctr, date1) values (3, '2C', date '2017-05-04');
insert into t2 (id, cctr, date1) values (4, '2B', date '2017-03-02');
insert into t2 (id, cctr, date1) values (5, '2B', date '2017-01-01');
insert into t2 (id, cctr, date1) values (6, 'UC', date '2016-11-23');
Quindi la query sarebbe:
select * from t2 where date1 = (
select max(date1)
from (
select
id, date1, cctr, lag(cctr) over(order by date1 desc) as prev
from t2
) x
where prev is not null and cctr <> prev
);
Risultato:
ID CCTR DATE1
------- ---------- -------------------
4 2B 2017-03-02 00:00:00
