Question

I have a table :

UNIQUE KEY ID      Clicks    INSERTDATE
 1         100001   10     2011-05-14 00:00:00.000
 2         100001   20     2011-05-13 00:00:00.000
 3         100001   30     2011-05-18 00:00:00.000
 4         100002   10     2011-05-20 00:00:00.000
 5         100002   15     2011-05-24 00:00:00.000
 6         100002   10     2011-05-05 00:00:00.000

I have a threshold value for clicks, lets say 20.

I need to write a T-SQL which should remove the clicks that do not meet the threshold of the accumulative Sum of clicks for each ID.

So for the above example ID “100001” has an accumulative clicks of 60 (10+20+30) but since the threshold is 20, the last record i.e. with the click value of 30 should get removed from the result.
However, the second record should still be included even though the sum at that point is > my threshold (10 + 20).

EDIT :

Another major rule that needs to be applied is that the INSERTDATE has to be ordered before performing any calculations

Any help would be much appreciated.

Answer 1

If I understood the question correctly, you’d like to filter on the RunningTotal for a given Id, like so:

select c1.*
from ClickTable c1
outer apply (
  select sum(Clicks) as RunningTotal
  from ClickTable 
  where pk < c1.pk
    and id = c1.id
) c2
where isnull(RunningTotal, 0) <= 20

this implies that you have a unique key field in the table, called PK.

Running sample: http://www.sqlfiddle.com/#!3/98173/11

Update

To order by Clicks instead of the primary key, just change the line

where pk < c1.pk

to

where Clicks < c1.Clicks

Running sample: http://www.sqlfiddle.com/#!3/31750/2