Column Concatenation

I have two columns, one with first names and one with last names. I created a new column in the table called full_names. How would I go about concatenating the first and last names (first_name||' '||last_name) and place them in this new column?

Would I use an insert command of some sort?

Thank you!
Deanna

update table1
set full_name = substrb(first_name||' '||last_name, 1, 80);

The substrb is just to make sure that none of the names are longer than the length of the new column (in this example, 80)

Thank you so much. The substring is a good idea.