Window functions operate on a group of rows and calculate a return value for every input row.

Before you define a window function in an Expression transformation, you need to describe the window by configuring the windowing properties. Windowing properties include a frame specification, partition keys, and order keys. The frame specification states which rows are included in the overall calculation for the current row. The partition keys determine which rows are in the same partition. The order keys determine how rows in a partition are ordered.

After you configure windowing properties, you define a window function in the Expression transformation. Informatica supports the window functions LEAD and LAG. You can also use aggregate functions as window functions in an Expression transformation.