|All functions, both built-in and UDF, are either deterministic or nondeterministic. A deterministic function always returns the same result. For example, when passed the same set of parameters, the DateAdd (built-in) function always returns the same date. The following statement|
SELECT DateAdd("mm",1,OrderDate) FROM Ordersadds one month to the value held in the OrderDate field in the Northwind sample database, as shown in the figure below.
|Result of a SELECT statement returns a predictable response|
A deterministic function must meet all four of the following conditions:
It also can’t call extended stored procedures, which are external routines (DLLs) written in a programming language like C.
- · It can’t access any table other than those defined by the function.
- · It can’t use built-in, nondeterministic functions.
- · It can’t call nondeterministic UDFs.