在PL/SQL中使用游标、动态sql和绑定变量的小例子

需求：查询并输出30号部门的雇员信息

方式一：使用 loop...fetch

 1 SET serveroutput ON;
 2 DECLARE
 3   CURSOR c_emp IS
 4     SELECT * FROM emp WHERE deptno = 30;
 5   v_emp emp%rowtype;
 6 BEGIN
 7   OPEN c_emp;
 8     loop
 9       fetch c_emp INTO v_emp;
10       exit WHEN c_emp%notfound;
11       dbms_output.put_line(v_emp.empno||‘  ‘||v_emp.ename||‘  ‘||v_emp.job||‘  ‘||v_emp.mgr||‘  ‘||v_emp.hiredate||‘  ‘||v_emp.sal||‘  ‘||v_emp.comm||‘  ‘||v_emp.deptno);
12     end loop;
13   close c_emp;
14 END;
15 /

方式二：使用游标 for 循环

 1 SET serveroutput ON;
 2 DECLARE
 3   CURSOR c_emp IS
 4     SELECT * FROM emp WHERE deptno = 30;
 5   v_emp emp%rowtype;
 6 BEGIN
 7   FOR e IN c_emp loop
 8     dbms_output.put_line(e.empno||‘  ‘||e.ename||‘  ‘||e.job||‘  ‘||e.mgr||‘  ‘||e.hiredate||‘  ‘||e.sal||‘  ‘||e.comm||‘  ‘||e.deptno);
 9   end loop;
10 END;
11 /

方式三：使用动态sql和绑定变量

 1 SET serveroutput ON;
 2 DECLARE
 3   TYPE emp_cursor IS REF CURSOR;
 4   c_emp emp_cursor;
 5   v_emp emp%rowtype;
 6 BEGIN
 7   OPEN c_emp FOR ‘select * from emp where deptno =:n‘ USING 30;
 8   loop
 9     fetch c_emp INTO v_emp;
10       exit WHEN c_emp%notfound;
11       dbms_output.put_line(v_emp.empno||‘  ‘||v_emp.ename||‘  ‘||v_emp.job||‘  ‘||v_emp.mgr||‘  ‘||v_emp.hiredate||‘  ‘||v_emp.sal||‘  ‘||v_emp.comm||‘  ‘||v_emp.deptno);
12   END loop;
13   close c_emp;
14 END;
15 /