So I have a table that holds a link relationship. Field1 is and ID and Filed2 is an ID. So far I've eliminated duplicate Field1\\Field2 combinations. However I still have cases where the inverse occurs. Meaning Field1 occurs as Field2 and Field2 occurs in Field1 for the same record. I tried a subquery within in inner join but it's returning way to many rows. Thanks in advance!
select a.field1, a.field2 from linktable
inner join (select field1, field2 from linktable) b on a.field1=b.field2 and a.field2=b.field1;
Sample data:
insert into linktable(field1, field2) values ('ABC', '123');
insert into linktable(field1, field2) values ('123', 'ABC');
I want to identify and remove cases where the above sample data occurs.
Something like this should get you the pairs:
SELECT a.field1, a.field2
FROM linktable a
JOIN linktable b ON (b.field1 = a.field2 AND b.field2 = a.field1)
Edit: An example of finding one of the pairs:
create table linktable(id number, field1 varchar2(32), field2 varchar2(32));
insert into linktable(id, field1, field2) values (1, 'ABC', '123');
insert into linktable(id, field1, field2) values (2, '123', 'ABC');
SELECT a.field1, a.field2, LEAST(a.id, b.id) AS id_to_delete
FROM linktable a
JOIN linktable b ON (b.field1 = a.field2 AND b.field2 = a.field1);
Result:
FIELD1 FIELD2 ID_TO_DELETE
123 ABC 1
ABC 123 1
Is this what you want?
select field1, field2
from (select field1, field2,
row_number() over (partition by least(field1, field2), greatest(field1, field2) order by field1) as seqnum
from t
) t
where seqnum = 1;
This returns one instance of field1
/ field2
regardless of ordering.
You should post sample data and expected result.
I think this query may work for you, this prevent the inverse occurs as field1, field2
= (x, y)
and (y, x)
SELECT field1, field2
FROM linktable
WHERE field1 >= field2;
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