On 9/12/2011 12:02 PM, Mr. Puneet Kishor wrote:
On Sep 12, 2011, at 6:51 AM, Igor Tandetnik wrote:
Something like this:
select geo.id, min_age, max_age, age_bottom, age_top, name, color
from geo left join intervals i on i.id = (
select id from intervals
where age_bottom>=
(select age_bottom from intervals where name = geo.max_age)
and age_top<=
(select age_top from intervals where name = geo.min_age)
order by (age_bottom - age_top) limit 1
);
Thanks Igor. The above does work and produces the correct result. The
query speed, however, is pretty slow ~ 75 seconds. So, I created
indexes on intervals.name, geo.max_age, and geo.min_age, and that
brought the query time to ~ 11 seconds. Still too slow.
Indexes on geo.max_age and min_age are unlikely to help with this query
(use EXPLAIN QUERY PLAN to see which indexes are actually used). An
index on intervals.age_bottom might. So would an index on
intervals.age_top (but not both at the same time).
--
Igor Tandetnik
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