sys.masked_columns (Transact-SQL)
Applies to: 
SQL Server 2016 (13.x) and later
Azure SQL Database
Azure SQL Managed Instance
Use the sys.masked_columns view to query for table-columns that have a dynamic data masking function applied to them. This view inherits from the sys.columns view. It returns all columns in the sys.columns view, plus the is_masked and masking_function columns, indicating if the column is masked, and if so, what masking function is defined. This view only shows the columns on which there is a masking function applied.
| Column name | Data type | Description |
|---|---|---|
| object_id | int | ID of the object to which this column belongs. |
| name | sysname | Name of the column. Is unique within the object. |
| column_id | int | ID of the column. Is unique within the object. Column IDs might not be sequential. |
| sys.masked_columns returns many more columns inherited from sys.columns. | various | See sys.columns (Transact-SQL) for more column definitions. |
| is_masked | bit | Indicates if the column is masked. 1 indicates masked. |
| masking_function | nvarchar(4000) | The masking function for the column. |
| generated_always_type | tinyint | Applies to: SQL Server 2016 (13.x) and later, SQL Database. 7, 8, 9, 10 only applies to SQL Database. Identifies when the column value is generated (will always be 0 for columns in system tables): 0 = NOT_APPLICABLE 1 = AS_ROW_START 2 = AS_ROW_END 7 = AS_TRANSACTION_ID_START 8 = AS_TRANSACTION_ID_END 9 = AS_SEQUENCE_NUMBER_START 10 = AS_SEQUENCE_NUMBER_END For more information, see Temporal Tables (Relational databases). |
Permissions
This view returns information about tables where the user has some sort of permission on the table or if the user has the VIEW ANY DEFINITION permission.
Example
The following query joins sys.masked_columns to sys.tables to return information about all masked columns.
SELECT tbl.name as table_name, c.name AS column_name, c.is_masked, c.masking_function
FROM sys.masked_columns AS c
JOIN sys.tables AS tbl
ON c.object_id = tbl.object_id
WHERE is_masked = 1;