Numerical variables in pqsql statements

Folks,

I'm sure this is dumb, but I'm a little confused about use of numerical variables in pqsql.  It was my impression one had to use EXECUTE on a concatenated string including quote_literal() for the variable containing the value.  This can be quite a bit of trouble.  I just wrote a function that included the statement :

 

CREATE TEMPORARY TABLE author_names AS
      SELECT ra.ref_auth_key, a.last_name, a.first_name
      FROM ref_auth ra INNER JOIN authors a
      ON (ra.author_num = a.author_key)
      WHERE ra.ref_num = refer_num;

 

where refer_num is integer.  This worked (surprisingly, to me).  So, what is the rule regarding variables?  Would this query work if I concatenated a string together, including quote_literal(refer_num) and then EXECUTEd it?

 

Thanks and sorry to be so stupid.