Hi,

I have to extract elements from a table ordered in a special way. For
example
select id,name from table_name order by age*weight;

It seems to be not efficient to order rows each time when I extract
information from the table. Is that possible to keep table-rows in
specific order? In other words I want to order rows of the table once
(and force the table to remember this order), so the mysql-server does
not need to order the rows each time when I "select" rows from the
table (because the rows in the table will be already in the correct
ordered).

And the second question. What should I do if i need NOT all rows of
the table but only top 10?

Thank you.

Kurda Yon wrote:
> Hi,
>
> I have to extract elements from a table ordered in a special way. For
> example
> select id,name from table_name order by age*weight;
>
> It seems to be not efficient to order rows each time when I extract
> information from the table. Is that possible to keep table-rows in
> specific order? In other words I want to order rows of the table once
> (and force the table to remember this order), so the mysql-server does
> not need to order the rows each time when I "select" rows from the
> table (because the rows in the table will be already in the correct
> ordered).
>
> And the second question. What should I do if i need NOT all rows of
> the table but only top 10?
>
> Thank you.

Create an index holding your chosen value

>
> Create an index holding your chosen value

Is that possible to extract only top 10 elements?

"Kurda Yon" <kurdayon@yahoo.com> schreef in bericht
news:cf45bcd7-fa0d-4cfb-9f3b-a3e21b9fa1de@k39g2000hsf.googlegroups.com...
> >
>> Create an index holding your chosen value
>
> Is that possible to extract only top 10 elements?

start reading:
http://dev.mysql.com/doc/refman/5.0/en/select.html
especially the part about LIMIT

>
> Create an index holding your chosen value
Do you mean "primary key"? The problem is that the column declared
with the primary key should hold _unique_ values. In my case, some
rows can have the same value of the argument which I want to use for
the ordering.

On 5 Feb, 00:46, Kurda Yon <kurda...@yahoo.com> wrote:
> > Create an index holding your chosen value
>
> Do you mean "primary key"? The problem is that the column declared
> with the primary key should hold _unique_ values. In my case, some
> rows can have the same value of the argument which I want to use for
> the ordering.

No, I mean create an index. An index can be a unique or a non-unique
index.