On 04/12/2014 06:29 AM, Rémi Cura wrote:
(please note that this random string function is NOT the good way to
do it, i should random int then use it as index to an array
containing all the letter)
Thanks a lot for this new version! It seems to be slower than your
first solution (no index use I guess, I gave up after 5 minutes vs 5
sec for the previous). Morevover, I canno't make assumption about a
fixed interval (2 sec in your example). But I think I see where you
are going.
After some test, the fastest is using BETWEEN and range. (it is way
faster than using the <@, strangely)
Here is the code :
Ah, sorry about that. I got pulled away to work on work stuff. I was trying
to figure out how to use an index on the range query, but not sure, without
adding a new column if it would even work.
I've never had the need for ranges yet, this is the first time I've gotten to
play with them.
I would not have thought about between like that, good call. I'd have never
guess it would be so fast.
If you can't use the fixed interval, then ranges are out.
I was thinking this could be improved:
select t,
(select t from a where a.t >= b.t order by a.t limit 1) as mint,
(select t from a where a.t < b.t order by a.t desc limit 1) as maxt
from b
It does two selects into a to find the nearest. Given this:
create table a(t float);
insert into a values (1), (5), (6);
could you write a single query to find the number nearest 3.5? If so we might
cut the work by 50%.
-Andy
PS: This list prefers you don't top post.
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