In a masking policy, the columns being masked as a group must belong to the same table. You can use the Shuffle, User Defined Function, Deterministic Substitution, and Random Substitution masking formats for group masking. The Deterministic Substitution and Random Substitution masking formats use data from another table to mask your sensitive data.

The following is an example of group masking using the Shuffle masking format. Suppose that you have customers from across the world. You have their details stored in a table, as shown below.

You don't want your developers to know the location of your customers. So, you want to mask the CITY, STATE and COUNTRY columns before sharing this data with the development team. But you want to have realistic masked data. For example, Richard lives in Santa Clara, California in the United States. After masking, if the city and state are Atlanta and Georgia respectively, India as the country is not valid. In this case, you want to ensure that the country remains the United States.

You can group these columns and use the Shuffle masking format to shuffle them together. After shuffling, your masked data might look like the data shown below.

This example shows you how to use the Deterministic Substitution masking format with group masking to mask sensitive data with data from another table. Suppose that you have customers from across the world. You have their details stored in a table, as shown below.

Let's assume that you want to use the data from the following table for group masking:

After masking these columns using the group masking option with the Deterministic Substitution masking format, your masked data might look like the data shown below.