Explicit invocation

You can use the EXECUTE PROCEDURE and EXECUTE FUNCTION statements to execute a UDR from:
  • A UDR
  • DB-Access
  • A client application (such as an ESQL/C application)

In addition, you can use a user-defined function in an SQL expression in the SELECT clause or WHERE clause. You cannot use a procedure in an SQL expression because a procedure does not return a value.