Newbie question - Auto enter into textfield via SQL

Question

I am not even sure what to put for the subject!!
I have a page that creates a new record in our leave tracking database.
The users are logging in via LDAP
The username is also in my employee table and can be used with a where statement
where "USERNAME" like :APP_USER
I want to bring in FIRSTNAME and LASTNAME and automatically put them in the form so the user does not have to.
I tried making the TEXTFIELD source a SQL query and I can get the data to load. When the record is submitted the data is not inserted into the new record it is blank.
The only way I can get the data to load is if the field source is set to Database Column.
My next efforts were to try and get the default value to be inserted via a SQL statement but as there is no option for SQL only it appears that I have to put in a PL/SQL Function body or expression.
I know that there needs to be a Declare then Begin and End but I do not know the syntax for what should be a reasonable simple query.
the sql for the records is
select "FIRSTNAME"
from "NWOCASTAFF"
where "USERNAME" like :APP_USER
the field I am trying to insert this default value is
P2_FIRST_NAME
it is a Text Field
I hope that someone can help me with this.
A small PS
If I wanted the text that is inserted to be Title Case how would I do that, with a format mask or is there some function like upper() which I can use.
thanks
John MP

Answer 1

Scott
Thanks for the code, it works perfectly! The field must be set to display as a textfield but other than that it is exactly what I need.
there is another thread that goes down the computation route
Query to set item default value
I may pursue that route if I find the default value SQL query to be too restrictive.