Re: help with SQL performance when using ORDER BY

[Charles Wilt <charles.wilt@xxxxxxxxx>]

If you want to select 100 rows, and then sort them...

Make sure that's what you're asking for.

with cte as (select * from table limit 100)
select * from cte order by fld1;


On Thu, Sep 24, 2020 at 4:09 AM Mark Villa <iseries.4.me@xxxxxxxxx> wrote:

> Hi all,
> I have been doing a lot of "SQL checking" recently and without breaking out
> the manuals, I am just curious what you guys do when you use ORDER BY. With
> tables greater than 10 or 20 mil rows it really tanks. Otherwise, my
> responses are usually subsecond.
>
> It makes the SQL engine (and myself) look dumb when I can't say
> "select these  100 rows" then ORDER THEM, don't look at 20 million rows,
> don't need anything sorted but the final set.
>
> --
> Thank You,
> Mark Villa
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