How the EXECUTE FUNCTION Statement Works

For a user-defined function to be executed with the EXECUTE FUNCTION statement, the following conditions must exist:

If EXECUTE FUNCTION specifies fewer arguments than the user-defined function expects, the unspecified arguments are said to be missing. Missing arguments are initialized to their corresponding parameter default values, if these were defined. The syntax of specifying default values for parameters is described in Routine Parameter List.

If the function name is not unique within the database, you must specify enough parameter_type information to disambiguate the name. See the section Arguments for additional information about how to specify parameters when invoking a function.

In Dynamic Server, the specific name of an external UDR is valid in some DDL statements, but is not valid in contexts where you invoke the function.

If Dynamic Server cannot resolve an ambiguous function name whose signature differs from that of another routine only in an unnamed-ROW type parameter, an error is returned. (This error cannot be anticipated by the database server when the ambiguous function is defined.)

INTO Clause

INTO Clause:
 
         .-,-----------------------------------------------------.
         V                                                       |
|--INTO----+-data_var--+-------------------------------------+-+-+--|
           |           |  (1)                                | |
           |           '--------+-:---------+--indicator_var-' |
           |                    |  (2)      |                  |
           |                    +--------$--+                  |
           |                    '-INDICATOR-'                  |
           '-data_structure------------------------------------'

Notes:

ESQL/C only
Informix extension

Element	Description	Restrictions	Syntax
data_structure	Structure that was declared as a host variable	Individual elements of structure must be compatible with the data types of the returned values	Language specific
data_var	Variable to receive the value that a user-defined function returns	See Data Variables.	Language specific
indicator_var	Program variable to store a return code if the corresponding data_var receives a NULL value	Use an indicator variable if the value of the corresponding data_var might be NULL	Language specific

You must include an INTO clause with EXECUTE FUNCTION to specify the variables that receive the values that a user-defined function returns. If the function returns more than one value, the values are returned into the list of variables in the order in which you specify them.

If the EXECUTE FUNCTION statement stands alone (that is, it is not part of a DECLARE statement and does not use the INTO clause), it must execute a noncursor function. A noncursor function returns only one row of values. The following example shows a SELECT statement in IBM Informix ESQL/C:

EXEC SQL execute function cust_num(fname, lname, company_name) into :c_num;