Professional Microsoft® SQL Server® 2008 Reporting Services

Appendix C. T-SQL System Variables and Functions

Variables and functions are often used interchangeably. SQL Server Books Online documents some variables as though they were functions. However, it's important to note that variables are used in expressions to obtain a value, whereas functions process specific business logic and may return a value. Many functions accept input arguments.

This Appendix, specific for SQL Server 2008, is not meant to be a comprehensive reference, but to provide a convenient guide to many functions and variables. For complete details and samples of usage, consult Books Online.

System Global Variables

The system-supplied global variables are organized into the following categories:

• Configuration

• Cursor

• System

• System Statistics

Configuration

Variable	Return Type	Description
@@DATEFIRST	tinyint	The system setting for the first day of the week: 1 = Monday 2 = Tuesday 3 = Wednesday 4 = Thursday 5 = Friday 6 = Saturday 7 = Sunday The U.S. default is 7.
@@DBTS	varbinary	The last assigned unique TimeStamp value
@@LANGID	smallint	The current language ID for the server: 0 = US English 1 = German 2 = French ... and so on.
@@LANGUAGE	nvarchar	The current language string for the server. Returns the language name in the native language form (us_english, Deutsch, Français, Dansk, Español, Italiano, etc.).
@@LOCK_TIMEOUT	int	Lock time-out setting for the current session in milliseconds (ms)
@@MAX_CONNECTIONS	int	The maximum concurrent connections setting for the server
@@MAX_PRECISION	tinyint	The maximum precision ...