Oracle 18c

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select * from V$VERSION;


BANNER
BANNER_FULL
BANNER_LEGACY
CON_ID


Oracle Database 18c Express Edition Release 18.0.0.0.0 - Production
Oracle Database 18c Express Edition Release 18.0.0.0.0 - Production
Version 18.4.0.0.0
Oracle Database 18c Express Edition Release 18.0.0.0.0 - Production
0


create table clientOrder (Idclient, Idorder, orderDate, Denial) as
    select 1, 11, date'2021-05-01'+0.5, 'n' from dual union all  
    select 1, 12, date'2021-05-02'+0.5, 'y' from dual union all  
    select 1, 13, date'2021-05-03'+0.5, 'n' from dual union all  
    select 2, 21, date'2021-05-01'+0.5, 'n' from dual union all  
    select 2, 22, date'2021-05-02'+0.6, 'y' from dual union all  
    select 2, 23, date'2021-05-03'+0.5, 'n' from dual union all  
    select 3, 31, date'2021-05-01'+0.5, 'n' from dual union all  
    select 3, 32, date'2021-05-01'+0.5, 'n' from dual union all  
    select 3, 33, date'2021-05-01'+0.5, 'n' from dual union all  
    select 4, 11, date'2021-05-01'+0.5, 'y' from dual union all  
    select 4, 11, date'2021-05-02'+0.5, 'n' from dual union all  
    select 4, 11, date'2021-05-03'+0.5, 'n' from dual union all  
    select 9, 99, date'2021-05-01'+0.5, 'n' from dual
13 rows affected

select * 
from clientOrder t1
where exists (
    select null from (
        select t2.*, lag (orderDate, 1, date'-4712-01-01') over (
            partition by Idclient order by orderDate asc) prevOrderDate
        from clientOrder t2
        where t2.Idclient = t1.Idclient)  
    where Denial = 'y' 
    and   orderDate-prevOrderDate <= 1)
and Denial = 'n'


IDCLIENT
IDORDER
ORDERDATE
DENIAL


1
11
01-MAY-21
n

1
13
03-MAY-21
n