Effective in version 10.2.2, you can use window functions to perform operations on groups of rows within a worksheet. The group of rows on which a function operates is called a window, which you define with a partition key, an order by key, and optional offsets. A window function calculates a return value for every input row within the context of the window.
You can use window functions to perform the following tasks:
- Retrieve data from previous or subsequent rows.
- Calculate a cumulative sum or a cumulative average based on a group of rows.
- Assign a sequential row number to each row in a group of rows.
- Replace null values in rows with the preceding non-null value within a group of rows.
- Generate session identifiers that you can use to group rows based on a specific time period, such as web site visits recorded in a log file.
You can apply multiple window functions to a worksheet. For example, you might apply a function to calculate the sum of values for each row following the current row within a window, and then apply another function to calculate the average of the same values.
Enterprise Data Lake adds a column containing the results of each function you apply to the worksheet.
For more information, see the "Prepare Data" chapter in the
Informatica 10.2.2 Enterprise Data Lake User Guide.