Expression transformation is used to perform any Non-aggregate calculations, conditional statements for single row. For example you might need to adjust the employee salaries, concatenate first and last names, convert string to numbers.
In this example we are Concatinating FIRST_NAME and LAST_NAME
1. Import the Source and target Definitions
2. Create a Mapping
3. Drag the Source Definition the mapping designer workspace.
4. Create an Expression transformation. Add one output port as follows and clear the output(O) for the first_name and last_name ports because we are going to use these ports as input only.
O_NAME= LAST_NAME|| ‘,’||FIRST_NAME
5.Drag and drop the target definition to workspace