Alban Hertroys ha scritto:
> Ottavio Campana wrote:
>> 2) how can I speed it up? by using indexes? or by changing the query?
>
> Do you have indices on mytable.id and copy_mytable.id?
> Does using NOT EXISTS get you any better results?
Eventually I had to select not all the table fields but only the primary
key and successively loop on the table again. Thus I've been able to
exploit the indexes.