创建函数返回 sys_refcursor

Question

How to create a function to display all employees of one department? I'd tried this code but it returns only "cursor" value.

CREATE OR REPLACE FUNCTION emp_dept (dept_id IN NUMBER)
RETURN SYS_REFCURSOR
IS 
emp_name SYS_REFCURSOR;

BEGIN
OPEN emp_name
FOR SELECT last_name
     FROM employees
    WHERE department_id = dept_id;

RETURN emp_name;
END emp_dept;

Answer 1

You may use these options to read and display output from the cursor that's returned from your function.

Use a simple select

select emp_dept(10) from dual;

Result

EMP_DEPT(10)        
--------------------
CURSOR STATEMENT : 1

CURSOR STATEMENT : 1

LAST_NAME                
-------------------------
Whalen

Use DBMS_SQL.RETURN_RESULT ( Oracle 12c and above)

DECLARE
l_cur SYS_REFCURSOR := emp_dept(10) ;
BEGIN
   DBMS_SQL.RETURN_RESULt(l_cur);
END;
/

Result

PL/SQL procedure successfully completed.

ResultSet #1


LAST_NAME                
-------------------------
Whalen

FETCH from the cursor into a local collection. A slight variation could be also be used to fetch into a scalar variable.

DECLARE
l_cur SYS_REFCURSOR := emp_dept(10) ;
TYPE l_last_name_tab IS TABLE OF employees.last_name%TYPE;
l_lnt l_last_name_tab;
BEGIN
   FETCH l_cur BULK COLLECT INTO l_lnt;

   for i in 1..l_lnt.count
   loop
    dbms_output.put_line(l_lnt(i));
   end loop;
END;
/

Result

Whalen


PL/SQL procedure successfully completed.