[thelist] Classic ASP: Someone else's code
Phil Turmel
philip at turmel.org
Tue Nov 22 12:07:49 CST 2005
Casey wrote:
> What exactly is going on here:
>
> if trim(Contact_First_x) & "" <> "" AND trim(Contact_Last_x) & "" <> "" then
>
> In case it's not clear in the email: "" <> "" which is: double-quote
> double-quote <> double-quote double-quote
>
> I'm not at all understanding the logic of this statement.... anyone?
>
> Casey
>
Casey,
This is a common shortcut to deal with null or empty values as if they
are zero-length strings. The above if statement is true if both first
and last names are null, empty, whitespace, or zero-length.
For most operators in ASP, VB, etc., any use of NULL falls through as
NULL to the result. But concatenation is treated differently: Null
becomes "".
Whenever I do this, I prefer the concatenation inside the trim for clarity:
trim(Contact_First_x & "") <> "" AND trim(Contact_Last_x & "") <> ""
HTH,
Phil
More information about the thelist
mailing list