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Posted by Erwin Moller on 07/20/05 11:48
bettina@coaster.ch wrote:
> I read somewhere that to gain efficiency it is advisable to avoid the
> use of select. But they don't explain why or what to use instead. Is it
> true? I habe a problem of speed (better to say of NO SPEED) but I don't
> know if it has something to do with the use of select.
> Waht can I use instead?
Hi,
Not sure, but maybe you misunderstood, and confused the above with SELECT *
and SELECT column1, column2.
SELECT * FROM tblusers;
is slower than
SELECT userid, username FROM tblusers;
So naming the columns is faster than using *, even if you select all
columns.
Reason is that the database has to retrieve the real columnnames first and
replace * with it, before executing the query.
Don't expect huge benefits though.
Besides that: If you use * instead of naming the columns, and the columns
you need are just a small subset of all columns, the naming of columns
clearly will be lot faster because the database has to deliver less data.
Regards,
Erwin Moller
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