I am having trouble with the following update query on an IB table:

update membernames
set username =
concat( substring( firstname, 1, 1 ),
substring( lastname, 1, 7 ))
where mbrnr = 1;

This gives Error -104 at the comma after firstname.

Any hints appreciated. I used Oracle's SQL reference for the concat syntax.
I also tried the || operator.

If there is a better SQL reference for use with IB I would appreciate a
pointer.

Happy holidays,

jwc