Re: help with SQL performance when using ORDER BY

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.

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Thank You,
Mark Villa
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