A. Kretschmer wrote:
am Wed, dem 13.09.2006, um 15:46:58 -0700 mailte Junkone folgendes:
hI
i have a bad situation that i did not have primary key. so i have a
table like this
colname1 colname2
1 apple
1 apple
2 orange
2 orange
It is a very large table. how do i remove the duplctes quickly annd
without much change.
begin;
alter table foo rename to tmp;
create table foo as select distinct * from tmp;
commit;
A couple potential problems here. First, you forgot to drop table tmp. But
maybe that is good thing because although the OP hasn't told us anything else
useful about the situation, and he has clearly contrived a simplistic facsimile
of his real problem, to be useful the table most likely either has foreign key
references, and/or is the primary key for other table foreign keys. You're
suggestion will break whatever application this data base supports because all
the foreign keys will point to table tmp rather than foo afterwards. Similarly,
there is the problem of any indexes on the table that would be lost. But I
suppose one can make the point that your suggestion is a great solution, given
the contrived example and insufficient problem understanding presented by the
OP -- I really think he needs more help than he realizes.
Regards,
Berend Tober
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