Logical Functions
There are two new functions in this category : CHOOSE and IIF.
CHOOSE
CHOOSE can be used to return a value from a list of values based on an index
number (note that index numbers start at 1). This function takes at least
2 arguments – the first argument must be an INT and the second argument
and onwards can be any data type.
SELECT CHOOSE (1, 'A', 'B', 'C', 'D', 'E' ) AS [Using CHOOSE] SELECT CHOOSE (4, 'A', 'B', 'C', 'D', 'E' ) AS [Using CHOOSE] --Returns NULL if the index value exceeds the bounds of the array of values passed SELECT CHOOSE (6, 'A', 'B', 'C', 'D', 'E' ) AS [Using CHOOSE]
IIF
If
you have prior experience working with other programming languages you may have already encountered the IIF conditional function which is a compact way of writing IF..THEN..ELSE clause which returns the value based on the condition evaluation. The first argument of this
function is a condition, if the condition is evaluated to TRUE then the second
expression is evaluated and returned, if the condition is evaluated to FALSE then the
third expression is evaluated and returned.
DECLARE @a int = 4; DECLARE @b int = 40; SELECT IIF ( @a > @b, 'Larger', 'Smaller' ) AS [Using CHOOSE] SELECT IIF (1=1, 5+6, 1+2 ) AS [Using CHOOSE] SELECT IIF (1=2, 5+6, 1+2 ) AS [Using CHOOSE]
String Functions
There are two new functions in this category – CONCAT and FORMAT.
CONCAT
You can pass two or more string
values to the CONCAT function the function combines them all into string. All
parameters passed to it of types other than a string will be converted to string
implicitly and a NULL value will be converted to empty string (zero length
string). The data type of the return value depends on the data type of the
arguments passed.
SELECT CONCAT ('Today ', 'is ', '3rd', '-', 'January') AS [Using CONCAT]
SELECT CONCAT ('Today ', 'is ', 3, 'rd', '-', 'January') AS [Using CONCAT]
FORMAT
This function formats and returns
the value passed to it in the specified format pattern. It returns a value of
type nvarchar in case of success or NULL in case if the format pattern or
culture is not valid. The performance of this function is slightly impaired as
it relies on .NET CLR.
SELECT FORMAT(GETDATE(), 'dd/MM/yyyy' ) AS [Using FORMAT] SELECT FORMAT(GETDATE(), 'dd-MMMM-yyyy') AS [Using FORMAT] SELECT FORMAT(GETDATE(), 'dddd, MMMM dd, yyyy') AS [Using FORMAT] SELECT FORMAT(GETDATE(), 'dd/MM/yyyy', 'en-US' ) AS [Using FORMAT]
Conclusion
In
this article I talked about 14 new built in functions in four different
categories coming up with SQL Server 2012 and which are going to make database
developers lifes easier. These new useful functions emulate the
functionality what we generally have in any other programming languages now at
T-SQL/database engine level.
Resources
Programmability
Enhancements (Database Engine)
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