database-principal-id-transact-sql.md

title	DATABASE_PRINCIPAL_ID (Transact-SQL) | Microsoft Docs
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DATABASE_PRINCIPAL_ID (Transact-SQL)

[!INCLUDEtsql-appliesto-ss2008-asdb-xxxx-xxx-md]

Returns the ID number of a principal in the current database. For more information about principals, see Principals (Database Engine).

Transact-SQL Syntax Conventions

Syntax

DATABASE_PRINCIPAL_ID ( 'principal_name' )  

Arguments

principal_name
Is an expression of type sysname that represents the principal.
When principal_name is omitted, the ID of the current user is returned. The parentheses are required.

Return types

int
NULL when the database principal does not exist

Remarks

DATABASE_PRINCIPAL_ID can be used in a select list, a WHERE clause, or anywhere an expression is allowed. For more information, see Expressions (Transact-SQL).

Examples

A. Retrieving the ID of the current user

The following example returns the database principal ID of the current user.

SELECT DATABASE_PRINCIPAL_ID();  
GO  

B. Retrieving the ID of a specified database principal

The following example returns the database principal ID for the database role db_owner.

SELECT DATABASE_PRINCIPAL_ID('db_owner');  
GO  

See also

Principals (Database Engine)
Permissions Hierarchy (Database Engine)
sys.database_principals (Transact-SQL)