利用FOR循环统计并输出各个部门的平均工资
DECLARE
  CURSOR c_1 IS SELECT deptno,avg(sal) avgsal FROM scott.emp GROUP BY deptno;
  v_dept c_1%rowtype;
begin
  FOR v_dept IN c_1
    loop
      dbms_output.put_line(v_dept.deptno||' '||v_dept.avgsal);
    end loop;
end;
简化1:
DECLARE
  CURSOR c_1 IS SELECT deptno,avg(sal) avgsal FROM scott.emp GROUP BY deptno;
begin
  FOR v_dept IN c_1
    loop
      dbms_output.put_line(v_dept.deptno||' '||v_dept.avgsal);
    end loop;
end;
简化2:
DECLARE
begin
  FOR v_dept IN (SELECT deptno,avg(sal) avgsal FROM scott.emp GROUP BY deptno)
    loop
      dbms_output.put_line(v_dept.deptno||' '||v_dept.avgsal);
    end loop;
end;

带UPDATE的游标
DECLARE
  v_empno scott.emp.empno%type;
  v_sal scott.emp.sal%type;
  CURSOR c_cursor IS SELECT empno,sal FROM scott.emp;
BEGIN
  OPEN c_cursor;
  LOOP
    FETCH c_cursor INTO v_empno,v_sal;
    EXIT WHEN c_cursor%NOTFOUND;
    IF v_sal<=1200 THEN
      UPDATE scott.emp SET sal = sal + 50 WHERE empno = v_empno;
      DBMS_OUTPUT.put_line('编码为'||v_empno||'工资已更新');
    END IF;
    dbms_output.put_line('记录数:'||c_cursor%rowcount);
  END LOOP;
  CLOSE c_cursor;
END;

DECLARE
  v_empno scott.emp.empno%type;
  v_sal scott.emp.sal%type;
  CURSOR c_cursor IS SELECT empno,sal FROM scott.emp WHERE sal<1200 FOR UPDATE;
BEGIN
  OPEN c_cursor;
  LOOP
    FETCH c_cursor INTO v_empno,v_sal;
    EXIT WHEN c_cursor%NOTFOUND;
    UPDATE scott.emp SET sal = sal + 50 WHERE current of c_cursor;
    dbms_output.put_line('编码为:'||v_empno||'工资已更新');
    dbms_output.put_line('记录数:'||c_cursor%rowcount);
  END LOOP;
  CLOSE c_cursor;
END;


带FOR UPDATE的游标
DECLARE
  cursor c_emp IS SELECT * FROM scott.emp FOR UPDATE;
  v_z1 NUMBER;
  v_emp c_emp%rowtype;
BEGIN
  FOR v_emp IN c_emp LOOP
    CASE v_emp.deptno
      WHEN 10 THEN v_z1:=100;
      WHEN 20 THEN v_z1:=150;
      WHEN 30 THEN v_z1:=200;
      ELSE v_z1:=200;
    END CASE;
    UPDATE scott.emp SET sal = sal + v_z1 WHERE CURRENT OF c_emp;
  END LOOP;
END;

用于更新的游标
DECLARE
  cursor c_1 IS SELECT empno,sal FROM scott.emp FOR UPDATE OF sal nowait;
  v_sal scott.emp.sal%type;
BEGIN
  FOR cursor_1 IN C_1
    LOOP
      IF cursor_1.sal<=1000 THEN 
      v_sal:=1500;
    ELSE
      v_sal:=cursor_1.sal*1.5;
      IF v_sal > 10000 THEN
      v_sal:=10000;
    END IF;
  END IF;
  UPDATE scott.emp SET sal = v_sal WHERE CURRENT OF c_1;
  END LOOP;
END;

游标变量示例
DECLARE
  TYPE t_dept IS REF cursor RETURN scott.emp%rowtype;
  c_1 t_dept;
  v_row scott.emp%rowtype;
BEGIN
  OPEN c_1 FOR SELECT * FROM scott.emp WHERE deptno = 10;
  FETCH c_1 INTO v_row;
  dbms_output.put_line(v_row.empno||' '||v_row.job);
  CLOSE c_1;
  
  OPEN c_1 FOR SELECT * FROM scott.emp WHERE sal>=2000;
  FETCH c_1 INTO v_row;
  dbms_output.put_line(v_row.empno||' '||v_row.job);
  CLOSE c_1;
END;