Conditional merge based on date

Question

Need help on a merge statement. I need to merge two dataset. But when the key match , I also need to cpmpared the date before I merege it.
See code below
drop table x1;
drop table y1;
select * from x1;
select * from y1;
create table x1 (id number,name varchar2(10),cdate date,status varchar2(1));
create table y1 (id number,name varchar2(10),cdate date,status varchar2(1));
insert into x1 select 1,'A',sysdate - 100,'Y' from dual;
insert into y1 select 1,'A',sysdate - 50,'N'  from dual ;--should change x1.status to y1.status  and x1.cdate to y1.cdate as y1.cdate > x1.cdate
insert into x1 select 2,'B',sysdate - 20,'Y' from dual;
insert into y1 select 2,'B',sysdate - 120,'N' from dual ;--should leave status in x1 alone
insert into y1 select 3,'c',sysdate - 10,'Y' from dual; --should do an insert on x1
commit;
--how do I do a conditional merge (key=id,name)
-- based on the cdate. If y1.cdate >= x1.cdate then take the y1.status  and y1.cdate
--desire output
select * from x1
1     A     01/01/2012 10:54:35 AM     N
2     B     1/31/2012 10:54:37 AM     Y
3     C     1/31/2012 10:54:37 AM     Y

Answer 1

Hi,
You can add a WHERE clause to the WHEN MATCHED THEN UPDATE section.
WHERE   x1.cdate  < y1.cdateThanks for posting the CREATE TABLE and INSERT statements; that's very helpful. It would also be helpful if you posted your MERGE statement, even if it's not working perfectly.