Re: Help me with this query!

First, I think commas will perform better than concatenation:

delete T1
where (C1, C2) in (select C1, C2 from T2);

However, depending on your data, you'll often-to-usually get beter mileage out of:

delete T1
where exists

   (
    select 'x'
    from T2
    where T2.C1 = T1.C1
    and T2.C2 = T1.C1
    )
/

Hope this helps,

Yosi

B N RAMAMOHAN wrote:

> Hi,
>
> I have a table T1 which has two columns C1 & C2 which are
> composite PK. There is another table T2 which contains part
> of these PK's (but they are not PKs here). Now I have to
> delete the rows from T1 for which PK values are in T2.
>
> One query that comes to my mind is:
>
> delete T1
> where C1||C2 in (select C1||C2 from T2);
>
> Is there any other efficient way of doing this?
>
> Please help me...
>
> Regards,
> Mohan
>
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--
Thanks,

Yosi


---------------------------------------------------------
Yosi Greenfield