Argument:
 
                                                (1)
|--+--------------+--+-| Subset of Expression |------+----------|
   '-parameter--=-'  +-NULL--------------------------+
                     '-(--singleton_select--)--------'
 

1. See Subset of Expressions Valid as an Argument

The CREATE PROCEDURE or CREATE FUNCTION statement can define a parameter list for a UDR. If the parameter list is not empty, you must enter arguments when you invoke the UDR. An argument is a specific value whose data type is compatible with that of the corresponding UDR parameter.

When you execute a UDR, you can enter arguments in either of two ways:

• With a parameter name (in the form parameter name = expression), even if the arguments are not in the same order as the parameters
• By position, with no parameter name, where each expression is in the same order as the parameter to which the argument corresponds. (This is sometimes called ordinal format.)

You cannot mix these two ways of specifying arguments within a single invocation of a routine. If you specify a parameter name for one argument, for example, you must use parameter names for all the arguments.

In the following example, both statements are valid for a user-defined procedure that expects three character arguments, t, d, and n:

EXECUTE PROCEDURE add_col (t ='customer', d ='integer', 
   n ='newint');

EXECUTE PROCEDURE add_col ('customer','newint','integer') ;