What is Set Variable in Pentaho Kettle

 

The Set Variable is used to set or declare variables to hold values usually database fields likewise you want to set start_date value which you have extracted from your time_dimension table using INPUT Step so that this start_date field will be accessible through out your script.

in the upper text filed named the step and then click the get fields button to have all desired table fields in the field name column that you have extracted using input step, in the second step name the variable to each field name and in the last column define its scope. In order to avoid null values that might come in your queries using INPUT for setting different variable the last column here to set default value that will be very useful let say if there is null value it will set it to default value.