Alpha Num and Alnum on empty string

[sangi1981]

Hi All,
I have a question.
What is the behavior of function:

Code: Select all

 AlNum, 
 Alpha and 
 Num

functions when input column is an empty string!?
Thanks

[manoj_23sakthi]

it gives false (0).
I think you are discuss about null string .

[sangi1981]

Ok thank you.
I discuss about not input column with null string, checked by IsNull(),
but about input column that may contain empty string, checked using function: Num(), Alpha(), Alnum().
So, if I have an empty string, like "", this functions return false (0)?

[Ravi.K]

Yes, the functions returns "0" if the input string is empty.

[ray.wurlod]

The most reliable is Len(InLink.TheString) which returns 0 for "" and a non-zero value for any other non-null string.