Re: Delete Duplicates with Using

Am 14.10.2017 um 08:20 schrieb Igal @ Lucee.org:
>
> Hello,
>
> I run the SQL query below to delete duplicates from a table. The
> subquery is used to identify the duplicated rows (row_num is a
> BIGSERIAL column).
>

other solution, using the CTID-column: (rows with (1,1,1) and (5,5,5)
are identical)

test=*# select * from dubletten ;
c1 | c2 | c3
----+----+----
1 | 1 | 1
1 | 1 | 1
1 | 2 | 3
2 | 3 | 4
3 | 4 | 5
4 | 5 | 5
5 | 5 | 5
5 | 5 | 5
(8 Zeilen)

test=*# with keep as (select max(ctid) as ctid from dubletten group by
c1,c2,c3) delete from dubletten where ctid not in (select ctid from keep);;
DELETE 2
test=*# select * from dubletten ;
c1 | c2 | c3
----+----+----
1 | 1 | 1
1 | 2 | 3
2 | 3 | 4
3 | 4 | 5
4 | 5 | 5
5 | 5 | 5
(6 Zeilen)

test=*#

Regards, Andreas

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