Re: [GENERAL] Except operation

Satyajeet Seth wrote:
>
> Hi
> The query:
> select * from webdata except select * from webdata1;
>  takes abysmally long .How can I optimise it?
> The particulars are:

You could try

  select * from webdata w
  where not exists
    (select * from webdata1 w1
     where w1.tid=w.tid
      ...
        )

If you have the correct indexes on webdata1 this can be quite fast.

Adriaan