Re: How to delete the not DISTINCT ON entries

If you do not have foreign key restrinctions, create a temp table from 
the select as:

CREATE TEMP TABLE tmp AS SELECT DISTINCT ON (location) location, time, 
report FROM weatherReports ORDER BY location, time DESC;

TRUNCATE weatherReports; INSERT INTO weatherReports SELECT * FROM tmp;

HTH


Achilleus Mantzios wrote:

> O kyrios Christoph Haller egrapse stis Jun 16, 2004 :
> 
> 
>>Referring to the DISTINCT ON example
>>
>>SELECT DISTINCT ON (location) location, time, report
>>FROM weatherReports
>>ORDER BY location, time DESC;
> 
> 
> maybe smth like 
> 
> delete from weatherReports where (location,time,report) not in 
> (SELECT DISTINCT ON (location) location, time, report FROM weatherReports 
> ORDER BY location, time DESC)
> 
> Note:
> Order by is very important, since it affects which rows are deleted.
> 
> 
>>How would I delete those entries skipped by the DISTINCT ON expression?
>>
>>TIA
>>
>>Regards, Christoph
>>
>>
>>
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> 
>