Configure Dynamic Data Masking on the email column in:

SalesLT.Customer

The column is normally:

EmailAddress

Use the built-in masking function:

email()

Microsoft documents that Dynamic Data Masking hides sensitive data in query results for nonprivileged users without changing the stored data. The built-in email() masking function exposes the first letter and returns the masked format aXXX@XXXX.com, which exactly matches the requirement.

Method 1 — SSMS / T-SQL Method

This is the fastest and most reliable method.

Step 1: Connect to db1

Open SQL Server Management Studio.

Connect to the Azure SQL logical server that hosts db1.

Open a query window against database:

db1

Step 2: Apply the email mask

Run:

ALTER TABLE [SalesLT].[Customer]

ALTER COLUMN [EmailAddress]

ADD MASKED WITH (FUNCTION = ' email() ' );

This adds a Dynamic Data Masking rule to the EmailAddress column. The actual email address remains stored in the table, but users without permission to view unmasked data will see the masked value. Microsoft’s documented syntax for adding an email mask is ALTER COLUMN Email ADD MASKED WITH (FUNCTION = ' email() ' ).

Step 3: Verify that the column is masked

Run:

SELECT

OBJECT_SCHEMA_NAME(mc.object_id) AS schema_name,

OBJECT_NAME(mc.object_id) AS table_name,

c.name AS column_name,

mc.masking_function

FROM sys.masked_columns AS mc

JOIN sys.columns AS c

ON mc.object_id = c.object_id

AND mc.column_id = c.column_id

WHERE OBJECT_SCHEMA_NAME(mc.object_id) = ' SalesLT '

AND OBJECT_NAME(mc.object_id) = ' Customer '

AND c.name = ' EmailAddress ' ;

Expected result:

schema_name SalesLT

table_name Customer

column_name EmailAddress

masking_function email()

Step 4: Test as a non-administrative user

If you have a test user, run:

EXECUTE AS USER = ' TestUser ' ;

SELECT TOP (10)

EmailAddress

FROM SalesLT.Customer;

REVERT;

Expected output should look like:

aXXX@XXXX.com

bXXX@XXXX.com

cXXX@XXXX.com

A user with administrative privileges, db_owner, or UNMASK permission can still see the original email value. Microsoft states that users with administrative rights such as server admin, Microsoft Entra admin, and db_owner can view the original unmasked data.

Method 2 — Azure Portal Method

Use this if the simulation expects portal configuration.

Step 1: Open db1

Sign in to the Azure portal.

Search for SQL databases.

Open database:

db1

Step 2: Open Dynamic Data Masking

From the db1 page:

Security > Dynamic Data Masking

Microsoft states that for Azure SQL Database, Dynamic Data Masking can be configured in the Azure portal from the SQL database configuration pane under Security > Dynamic Data Masking.

Step 3: Add a masking rule

Add a mask for the email column:

Setting

Value

Schema

SalesLT

Table

Customer

Column

EmailAddress

Masking field format

Email

Masking function

email()

Then select:

Save

The portal may show the mask type simply as:

Email

That is the correct option because it maps to the email() masking function.

Important Permission Check

Dynamic Data Masking only affects users who do not have permission to view unmasked data.

If a non-administrative user was previously granted UNMASK, remove it:

REVOKE UNMASK TO [UserName];

Or, if a role was granted UNMASK, revoke it from the role:

REVOKE UNMASK TO [RoleName];

Do not grant UNMASK to normal users. UNMASK allows users to bypass masking and see the original values. Microsoft documents that UNMASK permission controls whether users can view masked or original data.

Final Exam-Lab Action

Run this against db1:

ALTER TABLE [SalesLT].[Customer]

ALTER COLUMN [EmailAddress]

ADD MASKED WITH (FUNCTION = ' email() ' );

Then verify:

SELECT

OBJECT_SCHEMA_NAME(object_id) AS schema_name,

OBJECT_NAME(object_id) AS table_name,

name AS column_name,

masking_function

FROM sys.masked_columns

WHERE OBJECT_SCHEMA_NAME(object_id) = ' SalesLT '

AND OBJECT_NAME(object_id) = ' Customer '

AND name = ' EmailAddress ' ;

The task is complete when non-administrative users querying SalesLT.Customer.EmailAddress see masked email values such as:

aXXX@XXXX.com