Crystal Reports Boolean result expected?

Message

   I am a novice Crystal Report person and have been trying to figure out what I feel is a very simple report, but it is giving me fits.

I am searching for all entries which have a certain value and printing them out. However, I also want to grab those which do not have that value and still print them out.

For example, I want to pull the following entries from my DB:

1. All entries which are dated for yesterday.
2. All entries which have a value of SS1 for one of the keys.
3. All entries which do not have the value of SS1 (printed out with this field blank).

An example of the output for this report would look like:

Date      Name             Code
3/27       Smith              SS1
3/27       Maxwell          SS1
3/27       Johnson
3/27       Brown             SS1
3/27       Alcott               SS1
3/27       Howard      

I tried to do a formula like this:

if {rescode.code} = "SS1"
then "SS1"
else ""

However, I get an error because the formula should be returning a Boolean value, not a string.

How do I get this to work?

Thanks in advance!