Beginning Microsoft SQL Server 2008 ... - S3 Tech Training

Appendix A: System Functions
SUM
The SUM function will return the total of all values in expression. The syntax is as follows:
SUM([ALL | DISTINCT] )
SUM ignores NULL values. This function supports the OVER operator described in the ranking functions
section of this appendix.
VAR
The VAR function returns the variance of all values in expression. The syntax is as follows:
VAR()
VAR ignores NULL values. This function supports the OVER operator described in the ranking functions
section of this appendix.
VARP
The VARP function returns the variance for the population of all values in expression. The syntax is as
follows:
VARP()
VARP ignores NULL values. This function supports the OVER operator described in the ranking functions
section of this appendix.
Configuration Functions
Well, I’m sure it will come as a complete surprise (ok, not really…), but configuration functions are those
functions that tell us about options as they are set for the current server or database (as appropriate).
@@DATEFIRST
594
Returns the numeric value that corresponds to the day of the week that the system considers the first
day of the week.
The default in the United States is 7, which equates to Sunday. The values convert as follows:
❑ 1 — Monday (the first day for most of the world)
❑ 2 — Tuesday
❑ 3 — Wednesday