You use the CALL statement only to invoke a UDR from within an SPL program. You can use CALL to invoke both user-defined functions and user-defined procedures, as follows:
The following statement invokes the equal() function:
CALL equal (arg1, arg2) RETURNING result
You cannot use the CALL statement to invoke a user-defined function that contains an OUT parameter.
The following CALL statement invokes the log_compare() procedure:
CALL log_compare (arg1, arg2)