Re: case short circuits?

On 20 Jun 2005 16:46:09 -0700, "tq" <tomm_quinn_at_yahoo.com> wrote:

>Andy, thanks for the input. The example is helpful. Although I assumed
>as much from a logical standpoint, I was still curious to know since
>certain other functions such as nvl will not short-circuit regardless
>of the first argument being null or not.

 Well, I didn't know that, I assumed nvl() short-ciruited since that'd be sensible. I've started to use COALESCE more recently, since it's a more "Standard" function compared with the Oracle-specific NVL, and in the two-argument case it's equivalent, but can take more arguments when required. But it turns out it may even be more efficient, as it apparently does short-circuit:

SQL> select nvl(f1(), f2()) from dual;

NVL(F1(),F2())

             1
f1
f2

SQL> select coalesce(f1(), f2()) from dual;

COALESCE(F1(),F2())

                  1

-- 
Andy Hassall / <andy@andyh.co.uk> / <http://www.andyh.co.uk>
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