On Fri, Jun 22, 2001 at 12:45:34AM -0800, Amar Kumar Padhi wrote:
> if you are looking for one row only, then A and C will do. Since C involves
> a little bit of more coding and A does the same thing, A would be a better
> choice. But if you are coding to trap too many rows, then you should check
> for exceptions, all depends on your requirement.
Unless, of course, the select statement in question has an order by
clause. Since rownum is now generated before the ordering is applied,
you'll get the first row of the unordered set, and that row will then
be sorted. Not good.
>
> rgds
> amar
>
> -----Original Message-----
> Sent: Friday, June 22, 2001 12:36 AM
> To: Multiple recipients of list ORACLE-L
> betwe
>
>
> I have seen code that depends on the 8.1 behavior. It does bring up a
> question I have always wondered about. The question for the internals
> ubergeeks is: which of the following is best to use? (All should have the
> same result, so which one has the best performance and why?)
>
> A)
> declare
> y number;
> begin
> select x into y from z where rownum = 1;
> foo(y);
> end;
>
> B)
> declare
> y number;
> begin
> begin
> select x into y from z;
> exception
> when too_many_rows then null;
> end;
> foo(y);
> end;
>
> C)
> declare
> y number;
> cursor c is
> select x into y from z;
> begin
> open c;
> fetch c into y;
> close c;
> foo(y);
> end;
--
Tommy Wareing
Oxford English Dictionary
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