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Extracts the value from a column that is a specified number of rows after the current value.
  • The row from which to extract a value is determined by the order in which the rows are organized at the time that the transform is executed. 

  • If you are working on a randomly generated sample of your dataset, the values that you see for this function might not correspond to the values that are generated on the full dataset during job execution.

  • If the next value is missing or null, this function generates a missing value.
  • You can use the group and order parameters to define the groups of records and the order of those records to which this transform is applied.
  • This function works with the following transforms:

Basic Usage

Output: Returns the value in the row in the myNumber column immediately after the current row when the dataset is ordered by Date.

Syntax


ArgumentRequired?Data TypeDescription
col_refYstringName of column whose values are applied to the function
k_integerYinteger (positive)Number of rows after the current one from which to extract the value

For more information on the order and group parameters, see Window Transform.

For more information on syntax standards, see Language Documentation Syntax Notes.

col_ref

Name of the column whose values are used to extract the value that is k-integer values after the current one.

  • Multiple columns and wildcards are not supported.

Usage Notes:

Required?Data TypeExample Value
YesString (column reference)myColumn

k_integer

Integer representing the number of rows after the current one from which to extract the value.

  • Value must be a positive integer. For negative values, see PREV Function.
  • k=1 represents the immediately following row value.
  • If k is greater than or equal to the number of values in the column, all values in the generated column are missing. If a group parameter is applied, then this parameter should be no more than the maximum number of rows in the groups.
  • If the range provided to the function exceeds the limits of the dataset, then the function generates a null value.
  • If the range of the function is valid but includes missing values, the function generates a missing, non-null value.

Usage Notes:

 

Required?Data TypeExample Value
YesInteger4

Examples

Example - Examine prior order history

The following dataset contains order information for the preceding 12 months. You want to compare the current month's average against the preceding quarter. 

Source:

DateAmount
12/31/15118
11/30/156
10/31/15443
9/30/15785
8/31/1577
7/31/15606
6/30/15421
5/31/15763
4/30/15305
3/31/15824
2/28/15135
1/31/15523

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 Window
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 Window
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 Rename columns
Parameter: Option Manual rename
Parameter: Column window1
Parameter: New column name 'Amount_PriorQtr'

You can reformat this numeric value:

Transformation Name Edit column with formula
Parameter: Columns Amount_PriorQtr
Parameter: Formula NUMFORMAT(Amount_PriorQtr, '###.00')

You can use the following transform to calculate the net change. This formula computes the change as a percentage of the prior quarter and then formats it as a two-digit percentage.

Transformation Name New formula
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.

DateAmountAmount_PriorQtrNetChangePct_PriorQtr
12/31/15118411.33-71.31
11/30/156435.00-98.62
10/31/15443489.33-9.47
9/30/15785368.00113.32
8/31/1577596.67-87.1
7/31/15606496.3322.1
6/30/15421630.67-33.25
5/31/15763421.3381.09
4/30/15305494.00-38.26
3/31/15824329.00150.46
2/28/15135523.00-.74.19
1/31/15523  

 

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