The Workflow Manager provides an Expression Editor for any expression in the workflow. You can enter expressions using the Expression Editor for Link conditions, Decision tasks, and Assignment tasks.
The Expression Editor displays built-in variables, user-defined workflow variables, and predefined workflow variables such as $Session.status.
The Expression Editor also displays the following functions:
Transformation language functions.
SQL-like functions designed to handle common expressions.
Functions you create in PowerCenter based on transformation language functions.
Functions you create with the Custom Function API.