From: | Ketana Patel <contactketana(at)yahoo(dot)co(dot)in> |
---|---|
To: | Johann Spies <johann(dot)spies(at)gmail(dot)com> |
Cc: | "pgsql-general(at)postgresql(dot)org" <pgsql-general(at)postgresql(dot)org> |
Subject: | Re: Removing duplicates |
Date: | 2013-07-10 18:04:48 |
Message-ID: | 1373479488.45999.YahooMailNeo@web193801.mail.sg3.yahoo.com |
Views: | Raw Message | Whole Thread | Download mbox | Resend email |
Thread: | |
Lists: | pgsql-general |
Hi,
You can try following query on test database to remove duplicates.
DELETE FROM isi.rcited_ref a
WHERE a.ctid <> (SELECT min(ctid) FROM isi.rcited_ref b
WHERE a.rart_id = b.rart_id
AND a.r9 = b.r9
AND a.ra = b.ra
AND a.ry = b.ry
AND a.rw = b.rw
AND a.rv = b.rv
AND a.rp = b.rp
AND a.rs = b.rs
AND a.rart_id = 'A1986D733500019'
);
Regards,
Ketana
________________________________
From: Johann Spies <johann(dot)spies(at)gmail(dot)com>
To: "pgsql-general(at)postgresql(dot)org" <pgsql-general(at)postgresql(dot)org>
Sent: Wednesday, 10 July 2013 5:11 AM
Subject: [GENERAL] Removing duplicates
I have used this method successfully on another table but this one is not working.
I have a table of nearly 800 million records with some duplicates in.
Here is an example:
select rart_id, r9, ra, ry, rw, rv, rp, rs, ri
from isi.rcited_ref
where rart_id = 'A1986D733500019';
renders a result of 72 records. When I do
select count(id), rart_id, r9, ra, ry, rw, rv, rp, rs, ri
from isi.rcited_ref
where rart_id = 'A1986D733500019'
group by rart_id, r9, ra, ry, rw, rv, rp, rs, ri;
It shows that there are 36 duplicates with this rart_id.
So as a test I did the following (the id-field is the primary key):
DELETE FROM isi.rcited_ref q
WHERE EXISTS(SELECT 1 FROM isi.rcited_ref q1
WHERE q1.id != q.id
AND q.rart_id = q1.rart_id
AND q.r9 = q1.r9
AND q.ra = q1.ra
AND q.ry = q1.ry
AND q.rw = q1.rw
AND q.rv = q1.rv
AND q.rp = q1.rp
AND q.rs = q1.rs
AND q.rart_id = 'A1986D733500019'
);
But that deletes none. And I cannot see what went wrong.
I have also tried the same query with ctid without success:
DELETE FROM isi.rcited_ref q
WHERE EXISTS(SELECT 1 FROM isi.rcited_ref q1
WHERE q1.ctid < q.ctid
AND q.rart_id = q1.rart_id
AND q.r9 = q1.r9
AND q.ra = q1.ra
AND q.ry = q1.ry
AND q.rw = q1.rw
AND q.rv = q1.rv
AND q.rp = q1.rp
AND q.rs = q1.rs
AND q.rart_id = 'A1986D733500019'
);
The size of the table makes it difficult to use a 'group by' method to delete all duplcates.
What am I doing wrong?
Regards
Johann
--
Because experiencing your loyal love is better than life itself,
my lips will praise you. (Psalm 63:3)
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