in my data I have the following simplified table structure.

startdate

enddate

sum

2012-11-26

2012-11-28

5

2012-11-27

2012-11-30

2

2012-11-29

2012-12-01

3

...

...

...

Now what I want to get is the value from [sum] calculated for each single day. E.g. for 2012-11-27 it would be 7 (5 + 2). Is there a straight forward solution to do that in KNIME that I am just missing?

go with the "Moving Aggregation" node and check the "cumulative computation" option. Then create a manual aggregation taking the sum of the column "sum" and you should have your desired results.

first of all thank you for your fast reply.
Unfortunately your hint won´t solve my problem.

Maybe my example was to generic so let me explain it more precisely.
The value in the column "sum" is the occupancy somewhere. Between 2012-11-26 and 2012-11-28 5 people booked something.

2 people booked something between 2012-11-27 until 2012-11-30.

And now I want the final occupancy for the 2012-11-27.

How I get it? Of course the 2 people from above and also I have to add the 5 people who booked between 26th and 28th, because they include the 27th. Final occupancy is 7.

Finally I need this table structure:

date

occupancy

2011-11-26

5

2011-11-27

2

2011-11-28

2

2011-11-29

5

Any possible solutions how to solve this kind of problem?

ok... yeah that is somewhat more complex. Sorry for misreading (the cumulative sum and the sum per day were the same value so I fell for the bait ;-) )

Anyway, I have attached a workflow that solves your problem. The key is to first create one row per day for each booking period. After that it is possible to do a group by for each individual calendar date and calculate the sum of occupants on any given day.

BTW, I believe your example table in your most recent post is incorrect as I come up with the following based on your explanation of the problem and the example in your initial post: