It's more helpful to post create table and insert statements instead of Desc table and select * from table_name; http://tkyte.blogspot.com/2005/06/how-to-ask-questions.html
create table test_repeat(
cola number,
colb number,
colc varchar2(20)
);
insert into test_repeat values (1,1,'aaa');
insert into test_repeat values (1,2,'bbbb');
insert into test_repeat values (1,3,'cccc');
insert into test_repeat values (2,2,'dddd');
insert into test_repeat values (3,3,'eeee');
insert into test_repeat values (3,4,'ffff');
insert into test_repeat values (3,5,'gggg');
insert into test_repeat values (3,6,'hhhh');
insert into test_repeat values (4,4,'iiii');
insert into test_repeat values (5,5,'jjjj');
insert into test_repeat values (6,6,'kkkk');
insert into test_repeat values (6,7,'llll');
insert into test_repeat values (6,8,'mmmm');
commit;
1. You can use the Oracle analytic function Lead to look through your result set to see if colA is the same for the next row (after ordering it..) like..
select * from
(select colA, colb,
(case when colA = (lead(cola) over
(partition by colA order by cola, colb))
then 'Yes'
else 'No'
end) multiples,
colc
from test_repeat)
where colA = colb
/
COLA COLB MUL COLC
---------- ---------- --- --------------------
1 1 Yes aaa
2 2 No dddd
3 3 Yes eeee
4 4 No iiii
5 5 No jjjj
6 6 Yes kkkk
2. Or you can get the count for each value of COLA and compare it to see if there are duplicates...
select a.colA, a.colb, a.colc,
(case when (select count(*) from test_repeat t where t.cola = a.colA) > 1
then 'Yes'
else 'No'
end) Repeat
from test_repeat a
where colA = colB
/
COLA COLB COLC REP
---------- ---------- -------------------- ---
1 1 aaa Yes
2 2 dddd No
3 3 eeee Yes
4 4 iiii No
5 5 jjjj No
6 6 kkkk Yes
They are both equally simple ,but I would suggest the analytic function approach as I have found it to be generally faster for all Queries I have worked with in the past.
