Calculating percentiles

This is more of a mySQL/SQL question. Hope it applies
here...

I have a semi-large table (2000-3000 records and growing) in
which I
have stored a decimal for each row. This number is an
*absolute* rating
score for the record. I'd like to derive from this a
*relative* rating
for each record from .5-10, in .5 increments.

So I need to calculate which PERCENTILE each record is in,
and assign
the relative score accordingly.

For instance, if a record has a score of 1234.5, and I find
that it's
in the 65th percentile (65% of records have absolute scores
<= 1234.5),
then I would assign it a relative score of 6.5.

My question is, how do I figure the percentile score for
each record?

I anticipate that this will be run as a batch process on a
nightly
basis, but I'm open to suggestions.

THANKS in advance!
- Ryan


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do you plan to include php or just purely sql ?


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