EXAMPLE  NEXT Function
This example covers how to use the NEXT function to create windows of data from the current row and subsequent (next) rows in the dataset. You can then apply rolling computations across these windows of data.
Functions:
Item  Description 

NEXT Function  Extracts the value from a column that is a specified number of rows after the current value. 
ROLLINGAVERAGE Function  Computes the rolling average of values forward or backward of the current row within the specified column. 
NUMFORMAT Function  Formats a numeric set of values according to the specified number formatting. Source values can be a literal numeric value, a function returning a numeric value, or reference to a column containing an Integer or Decimal values. 
Source:
The following dataset contains order information for the preceding 12 months. You want to compare the current month's average against the preceding quarter.
Date  Amount 

12/31/15  118 
11/30/15  6 
10/31/15  443 
9/30/15  785 
8/31/15  77 
7/31/15  606 
6/30/15  421 
5/31/15  763 
4/30/15  305 
3/31/15  824 
2/28/15  135 
1/31/15  523 
Transformation:
Using the ROLLINGAVERAGE
function, you can generate a column containing the rolling average of the current month and the two previous months:
Transformation Name 


Parameter: Formulas  ROLLINGAVERAGE(Amount, 3, 0) 
Parameter: Order by  Date 
Note the sign of the second parameter and the order
parameter. The sort is in the reverse order of the Date
parameter, which preserves the current sort order. As a result, the second parameter, which identifies the number of rows to use in the calculation, must be positive to capture the previous months.
Technically, this computation does not capture the prior quarter, since it includes the current quarter as part of the computation. You can use the following column to capture the rolling average of the preceding month, which then becomes the true rolling average for the prior quarter. The window
column refers to the name of the column generated from the previous step:
Transformation Name 


Parameter: Formulas  NEXT(window, 1) 
Parameter: Order by  Date 
Note that the order parameter must be preserved. This new column, window1
, contains your prior quarter rolling average:
Transformation Name 


Parameter: Option  Manual rename 
Parameter: Column  window1 
Parameter: New column name  'Amount_PriorQtr' 
You can reformat this numeric value:
Transformation Name 


Parameter: Columns  Amount_PriorQtr 
Parameter: Formula  NUMFORMAT(Amount_PriorQtr, '###.00') 
You can use the following transformation to calculate the net change. This formula computes the change as a percentage of the prior quarter and then formats it as a twodigit percentage.
Transformation Name 


Parameter: Formula type  Single row formula 
Parameter: Formula  NUMFORMAT(((Amount  Amount_PriorQtr) / Amount_PriorQtr) * 100, '##.##') 
Parameter: New column name  'NetChangePct_PriorQtr' 
Results:
Note
You might notice that there are computed values for Amount_PriorQtr
for February and March. These values do not factor in a full three months because the data is not present. The January value does not exist since there is no data preceding it.
Date  Amount  Amount_PriorQtr  NetChangePct_PriorQtr 

12/31/15  118  411.33  71.31 
11/30/15  6  435.00  98.62 
10/31/15  443  489.33  9.47 
9/30/15  785  368.00  113.32 
8/31/15  77  596.67  87.1 
7/31/15  606  496.33  22.1 
6/30/15  421  630.67  33.25 
5/31/15  763  421.33  81.09 
4/30/15  305  494.00  38.26 
3/31/15  824  329.00  150.46 
2/28/15  135  523.00  .74.19 
1/31/15  523 