[thelist] get avg of last 3 records in SQL
shawn allen
shawn at alterior.net
Thu Nov 7 14:28:01 CST 2002
quoth Jason Bauer:
[from somebody else]:
> > how can i get the average of the last 3 records entered by a
> > particlar user? or even just the last 3 records and do the math
> > elsewhere.
You might also consider using a view, and simply selecting the avg of
the attribute from there. For instance, in PostgreSQL:
CREATE VIEW most_recent_rows AS
SELECT relevant_attribute
FROM relevant_table
ORDER BY relevant_attribute DESC
LIMIT 3;
SELECT avg(relevant_attribute) FROM most_recent_rows;
If you're using MySQL, you won't have views at your disposal, but a
temporary table would work similarly on a connection-by-connection
basis. As far as qualifying your query to return only the "last 3
records", well, that varies infinitely with table schema, so I'll leave
that to you ;)
--
shawn allen
e: shawn at alterior.net
p: 415 577 3961
im: shawnpallen
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