State the first_defined function with an example - Abinitio

State the first_defined function with an example.

- This function is similar to the function NVL() in Oracle database

- It performs the first values which are not null among other values available in the function and assigns to the variable

Example: A set of variables, say v1,v2,v3,v4,v5,v6 are assigned with NULL.
Another variable num is assigned with value 340 (num=340)
num = first_defined(NULL, v1,v2,v3,v4,v5,v6,NUM)
The result of num is 340