Access next row data

bea11005

Hello.

I'm doing my final work at university and I get some doubts.

In first place I wanna know if there's some way to access data in the next row.

In order to access previous row data I used Lag series operator but I can't find the way to do so on the next register.

 

My data is like this:

Discussion  Userid   Parent  Created   Modified

1                  1           0           12            14

1                  2           82         15            16

1                  1           85          17            20

1                  3           85         22             24

2                  45         0           26             32

2                  48         89         33             34

2                  46         90         34             35

I wanna calculate, for each userid, difference between modified(i+1)-created(i).

The attribute parent=0 means that's the first message on a discussion.

With that I wanna to calculate how many time is the between a message from a userid and his response.

For the first row I wanna 1 1 0 (16-12)=4

How can I do that? Is there a way to know what row corresponds to the last message of a discussion? How can I underline the previous row of a row with parent=0?

Thomas_Ott

You can generate temporary unique ids using the Generate ID operator upstream and do the joins downstream. Then you can use a Select Attributes with invert toggled on to select that ID column attribute out. I do this all the time.