On 8 Jun 2009, at 19:01, David Fetter wrote:
Hello!
I've the following data:
datetime | val1 | val2
time1 | 4 | 40%
time2 | 7 | 30%
time3 | 12 | 20%
...
I'd like to sum up the following:
(7-4)*30% + (12-7)*20% + ...
This is best done in 8.4 using Windowing. Sadly, it's an 8.4-only
feature, and dodgy hacks are the rule until you can use them.
Cheers,
David.
I do this type of thing now and again using a self join with an offset.
select test_a.val1 - test_b.val1
from test test_a inner join test test_b
on test_a.pkey = test_b.pkey - 1;
Thought I was quite clever the first time, didn't know it was a dodgy
hack! I'm trying to learn more about windowing before 8.4, how would
this example be done with that?
Regards
Oliver
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