- If an input value is missing or null, it is not factored in the computation. For example, for the first row in the dataset, the rolling calculation of previous values is undefined.
The row from which to extract a value is determined by the order in which the rows are organized based on the
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.
- Required column name
- Required kth value, which is a positive integer
- Two optional integer parameters that determine the window backward and forward of the current row. The default integer parameter values are
0, which computes the rolling function from the current row back to the first row of the dataset.
- This function works with the following transforms:
derive type:single value:ROLLINGKTHLARGESTUNIQUE(myCol, 2)
Output: Generates a new column containing the rolling second largest unique value in the
myCol column from the first row of the dataset to the current one.