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sys.system_columns (Transact-SQL)

Applies to: SQL Server Azure SQL Database Azure SQL Managed Instance Azure Synapse Analytics Analytics Platform System (PDW) SQL analytics endpoint in Microsoft Fabric Warehouse in Microsoft Fabric

Contains a row for each column of system objects that have columns.

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 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 the 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 declared to use filestream storage.
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 Non-zero if the column data type 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 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. Or, 0 if there is 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 Column Sets.
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).
generated_always_type_desc nvarchar(60) Applies to: SQL Server 2016 (13.x) and later, SQL Database.

Textual description of generated_always_type's value (always NOT_APPLICABLE for columns in system tables)

NOT_APPLICABLE
AS_ROW_START
AS_ROW_END

Applies to: Starting with SQL Server 2022 (16.x), SQL Database

AS_TRANSACTION_ID_START
AS_TRANSACTION_ID_END
AS_SEQUENCE_NUMBER_START
AS_SEQUENCE_NUMBER_END
ledger_view_column_type tinyint Applies to: Starting with SQL Server 2022 (16.x), SQL Database.

If not NULL, indicates the type of a column in a ledger view:

1 = TRANSACTION_ID
2 = SEQUENCE_NUMBER
3 = OPERATION_TYPE
4 = OPERATION_TYPE_DESC

For more information on database ledger, see Ledger.
ledger_view_column_type_desc nvarchar(60) Applies to: Starting with SQL Server 2022 (16.x), SQL Database.

If not NULL, contains a textual description of the the type of a column in a ledger view:

TRANSACTION_ID
SEQUENCE_NUMBER
OPERATION_TYPE
OPERATION_TYPE_DESC

Permissions

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

See Also

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