Store Groovy SQL result as a variable? - sql

Question

I am very, very new to Groovy (like two days in). I am trying to take a SQL result which will return a single value, and store that value so that it can be put in the body of an email. However, my SQL result always returns NULL, but the other values in the email work just fine.
I know that the result will only return a single value, so how in the world can I get that value stored as a string?
def sql = getSqlInstance()
def user = "\'" + trmCurrentUser.username + "\'";
def name = "\'" + trmCurrentUser.displayname + "\'";
def email = "\'" + trmCurrentUser.email + "\'";
def comm = "\'" + trmComponent.id + "\'";
def rslt=[];
def cmpgn;
rslt[0] = sql.firstRow("select activity_id from DB.TABLE where communication_id=${comm}");
def cmpgn = rslt[0];
toAddress = trmCurrentUser.email;
fromAddress = "me#email.com";
trmUtilities.sendEmail (
//self explanatory
toAddress, fromAddress,
//body of email
user + " " + name + " " + email + " " + comm + " " + cmpgn[0],
//subject of email
" Action on " + trmComponent.componentType + " " + trmComponent.name
);
The resulting email I get is this (with the appropriate values other than the NULL):
'MYID' 'MY NAME' 'MYEMAIL' 'COMM' null