QUESTION NO: 26
Which two statements are true regarding single row functions? (Choose two.)
A. They can be nested only to two levels
B. They always return a single result row for every row of a queried table
C. Arguments can only be column values or constant
D. They can return a data type value different from the one that is referenced
E. They accept only a single argument
Answer: B,D
答案解析：
参考：4：http://blog.csdn.net/rlhua/article/details/12909823
Explanation:
A function is a program written to optionally accept input parameters, perform an operation, or
return a single value. A function returns only one value per execution.
Three important components form the basis of defining a function. The first is the input parameter
list. It specifies zero or more arguments that may be passed to a function as input for processing.
These arguments or parameters may be of differing data types, and some are mandatory while
others may be optional. The second component is the data type of its resultant value. Upon
execution, only one value is returned by the function. The third encapsulates the details of the
processing performed by the function and contains the program code that optionally manipulates
the input parameters, performs calculations and operations, and generates a return value.