how to delete corresponding matching rows in Oracle SQL? - oracle

Question

I'm trying to delete rows in a table only when there is a corresponding entry with a negative amount. The tricky part is there could be more positive than negative or more negative than positive.
value1 amt
12345 50
12345 50
12345 -50
12345 -50
abcde 40
abcde 40
abcde -40
11111 30
11111 -30
11111 -30
The result should be:
abcde 40
11111 -30

Answer 1

I have to apologize. I realized the posters data set was too simple. Here is a revised answer that I believe works.
Basically, you need to partition into pairs and then delete the pairs having sum() = 0.
create table t ( id varchar2(20), val number );
delete from t;
INSERT INTO t ( id, val ) values ( '12345', 50);
INSERT INTO t ( id, val ) values ( '12345', 50);
INSERT INTO t ( id, val ) values ( '12345', -50);
INSERT INTO t ( id, val ) values ( '12345', -50);
INSERT INTO t ( id, val ) values ( 'abcde', 40);
INSERT INTO t ( id, val ) values ( 'abcde', 40);
INSERT INTO t ( id, val ) values ( 'abcde', 20);
INSERT INTO t ( id, val ) values ( 'abcde', 40);
INSERT INTO t ( id, val ) values ( 'abcde', -40);
INSERT INTO t ( id, val ) values ( '11111', 30);
INSERT INTO t ( id, val ) values ( '11111', -30);
INSERT INTO t ( id, val ) values ( '11111', -30);
INSERT INTO t ( id, val ) values ( 'aaaaa', 10);
INSERT INTO t ( id, val ) values ( 'aaaaa', -30);
COMMIT;
MERGE INTO t
USING (WITH value_partition AS
(SELECT t.*,
ROW_NUMBER () OVER (PARTITION BY t.id, t.val ORDER BY ROWID) rn_in_value
FROM t)
SELECT sp.ROWID row_id,
sp.*,
CASE WHEN SUM (sp.val) OVER (PARTITION BY sp.id, ABS (sp.val), rn_in_value) = 0 THEN 'N' ELSE 'Y' END
keep_row
FROM value_partition sp) u
ON (t.ROWID = u.row_id
AND u.keep_row = 'N')
WHEN MATCHED THEN
UPDATE SET t.val = u.val
DELETE
WHERE u.keep_row = 'N';
SELECT * FROM t;