MySQL - How to SELECT based on value of another SELECT

Question

I have a table that looks something like this:

Name    Year   Value
 A      2000     5
 A      2001     3
 A      2002     7
 A      2003     1
 B      2000              


        

Answer 1

SELECT x.name, x.summary, (x.summary / COUNT(*)) as percents_of_total
FROM tbl t
INNER JOIN 
(SELECT name, SUM(value) as summary
FROM tbl
WHERE year BETWEEN 2000 AND 2001
GROUP BY name) x ON x.name = t.name
GROUP BY x.name, x.summary