sys.columns (Transact-SQL)

THIS TOPIC APPLIES TO: yesSQL Server (starting with 2008)yesAzure SQL DatabaseyesAzure SQL Data Warehouse yesParallel Data Warehouse

Returns a row for each column of an object that has columns, such as views or tables. The following is a list of object types that have columns:

  • Table-valued assembly functions (FT)

  • Inline table-valued SQL functions (IF)

  • Internal tables (IT)

  • System tables (S)

  • Table-valued SQL functions (TF)

  • User tables (U)

  • Views (V)

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.
system_type_id tinyint ID of the system type of the column.
user_type_id int ID of the type of the column as defined by the user.

To return the name of the type, join to the sys.types catalog view on this column.
max_length smallint Maximum length (in bytes) of the column.

-1 = Column data type is varchar(max), nvarchar(max), varbinary(max), or xml.

For text columns, the max_length value will be 16 or the value set by sp_tableoption 'text in row'.
precision tinyint Precision of the column if numeric-based; otherwise, 0.
scale tinyint Scale of column if numeric-based; otherwise, 0.
collation_name sysname Name of the collation of the column if character-based; otherwise, NULL.
is_nullable bit 1 = Column is nullable.
is_ansi_padded bit 1 = Column uses ANSI_PADDING ON behavior if character, binary, or variant.

0 = Column is not character, binary, or variant.
is_rowguidcol bit 1 = Column is a declared ROWGUIDCOL.
is_identity bit 1 = Column has identity values
is_computed bit 1 = Column is a computed column.
is_filestream bit 1 = Column is a FILESTREAM column.
is_replicated bit 1 = Column is replicated.
is_non_sql_subscribed bit 1 = Column has a non-SQL Server subscriber.
is_merge_published bit 1 = Column is merge-published.
is_dts_replicated bit 1 = Column is replicated by using SSIS.
is_xml_document bit 1 = Content is a complete XML document.

0 = Content is a document fragment or the column data type is not xml.
xml_collection_id int Nonzero if the data type of the column is xml and the XML is typed. The value will be the ID of the collection containing the validating XML schema namespace of the column.

0 = No XML schema collection.
default_object_id int ID of the default object, regardless of whether it is a stand-alone object sys.sp_bindefault, or an inline, column-level DEFAULT constraint. The parent_object_id column of an inline column-level default object is a reference back to the table itself.

0 = No default.
rule_object_id int ID of the stand-alone rule bound to the column by using sys.sp_bindrule.

0 = No stand-alone rule. For column-level CHECK constraints, see sys.check_constraints (Transact-SQL).
is_sparse bit 1 = Column is a sparse column. For more information, see Use Sparse Columns.
is_column_set bit 1 = Column is a column set. For more information, see Use Sparse Columns.
generated_always_type tinyint Applies to: SQL Server 2016 through SQL Server 2017, SQL Database.

The numeric value representing the type of column (value will always be 0 for columns in system tables):

0 = NOT_APPLICABLE

1 = AS_ROW_START

2 = AS_ROW_END

For more information about Always Encrypted, see Always Encrypted (Database Engine).
generated_always_type_desc nvarchar(60) Applies to: SQL Server 2016 through SQL Server 2017, SQL Database.

The text description of the type of column (value will always be NOT_APPLICABLE for columns in system tables):

NOT_APPLICABLE

AS_ROW_START

AS_ROW_END
encryption_type int Applies to: SQL Server 2016 through SQL Server 2017, SQL Database.

Encryption type:

1 = Deterministic encryption

2 = Randomized encryption
encryption_type_desc nvarchar(64) Applies to: SQL Server 2016 through SQL Server 2017, SQL Database.

Encryption type description:

RANDOMIZED

DETERMINISTIC
encryption_algorithm_name sysname Applies to: SQL Server 2016 through SQL Server 2017, SQL Database.

Name of encryption algorithm.

Only AEAD_AES_256_CBC_HMAC_SHA_512 is supported.
column_encryption_key_id int Applies to: SQL Server 2016 through SQL Server 2017, SQL Database.

ID of the CEK.
column_encryption_key_database_name sysname Applies to: SQL Server 2016 through SQL Server 2017, SQL Database.

The name of the database where the column encryption key exists if different than the database of the column. NULL if the key exists in the same database as the column.
is_hidden bit Applies to: SQL Server 2017 through SQL Server 2017, SQL Database.

Indicates if the column is hidden:

0 = regular, not-hidden, visible column

1 = hidden column
is_masked bit Applies to: SQL Server 2017 through SQL Server 2017, SQL Database.

Indicates if the column is masked by a dynamic data masking:

0 = regular, not-masked column

1 = column is masked

Permissions

The visibility of the metadata in catalog views is limited to securables that a user either owns or on which the user has been granted some permission. For more information, see Metadata Visibility Configuration.

See Also

System Views (Transact-SQL)
Object Catalog Views (Transact-SQL)
Catalog Views (Transact-SQL)
Querying the SQL Server System Catalog FAQ
sys.all_columns (Transact-SQL)
sys.system_columns (Transact-SQL)