Sometimes, you need to apply complex logic to your data that can't be easily expressed in SQL. One option is to wrap your logic in a User Defined Function (UDF). What if you already have this logic coded in a language that is not supported by UDF? Script Table Operator is a Teradata feature that allows you to bring your logic to the data and run it on Teradata. The advantage of this approach is that you don't have to retrieve data from Teradata to operate on it. Also, by running your data applications on Teradata, you leverage its parallel nature. You don't have to think how your applications will scale. You can let Teradata take care of it.