Re: DELETE FROM t WHERE EXISTS - Mailing list pgsql-sql

From Dmitry Tkach
Subject Re: DELETE FROM t WHERE EXISTS
Date
Msg-id 3E5FE6E8.9020200@openratings.com
Whole thread Raw
In response to DELETE FROM t WHERE EXISTS  ("Dan Langille" <dan@langille.org>)
List pgsql-sql
What about

select * into temp rows_to_keep from clp order by commit_date limit 100;
truncate clp;
insert into clp select * from rows_to_keep;

Dima.



Dan Langille wrote:
> Hi folks,
> 
> I wanted to delete "old" rows from a table.  These are the rows I 
> want to keep:
> 
> SELECT * 
> FROM clp 
> ORDER BY commit_date 
> LIMIT 100
> 
> So I tried this:
> 
> DELETE FROM clp 
> WHERE NOT EXISTS (
> SELECT * 
> FROM clp 
> ORDER BY commit_date 
> LIMIT 100);
> 
> Uhh uhh, nothing deleted.  I don't understand why.
> 
> OK, I can do this instead:
> 
> DELETE from clp 
> where commit_log_id NOT in (
> SELECT commit_log_id 
> FROM clp 
> ORDER BY commit_date 
> LIMIT 100);
> 
> Can you think of a better way?



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