| query optimisation [message #3037] |
Sun, 01 September 2002 21:08  |
Deepa
Messages: 269
Registered: November 2000
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Senior Member |
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hi,
i want to delete the duplicate records .but one copy of the duplicate record should be present in the table.
i am using the following query.
delete from test a where a.rowid not in (select max(b.rowid) from test b where b.rowid=a.rowid).the above query is taking more time if i have some 60000 records.
i want the query to be optimised to do that function.
thanks,
deepa
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| Re: query optimisation [message #3050 is a reply to message #3037] |
Mon, 02 September 2002 06:38  |
Mark
Messages: 284
Registered: July 1998
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Senior Member |
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I don't imagine that this is any quicker, but feel free to give it a try ...
delete from TABLE
where rowid in (
select min(rowid)
from TABLE T2
having count(UNIQUE)>1
group by UNIQUE
);
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