Hi.
On Fri 2003-01-31 at 17:22:37 -0000, [EMAIL PROTECTED] wrote:
[...]
> select count(*) from percentile where <criteria>;
>
> Work out 95% or this value.
>
> create temporary table percentile (id int unsigned auto_increment
> primary key, scantime decimal(20,10));
>
> insert into percentile (scantime) select processingtime from emails
> where <same criteria> order by processingtime desc limit <value from
> above>;
>
> select min(scantime) from percentile;
If I am not mistaken, you can pick the row in question without a
separat table:
Basically you limit the query to the first n rows (in descending
order) and then pick the one with the lowerst value, which should have
been the last in the limited range. So you could pick that row
directly, I think:
SELECT processingtime FROM emails
WHERE <blah> ORDER BY processingtime DESC LIMIT <value>,1
Second, why use 95% of the table, if you can do with 5%? In other
words, calculate the remainder, sort ascending and limit by the
remainder you calculated. The difference should especially in your
case, where you copy those rows and can avoid to do so for 90% of the
columns.
HTH,
Benjamin.
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