mysql游标的概述_MySQL游标简介
mysql> delimiter //
mysql>
mysql> create procedure test1()
-> begin
-> declare l_add_bonus1 int default 1000;
-> declare l_add_bonus2 int default 500;
-> declare l_empno int;
-> declare l_sal,l_bonus decimal(15,2);
->
-> -- 游标结束的标志
-> declare done int default 0;
->
-> -- 声明游标
-> declare emp_cur cursor for select empno,sal,comm from emp;
->
-> -- 指定游标循环结束时的返回值
-> declare continue handler for not found set done =1;
->
-> -- 打开游标
-> open emp_cur;
->
-> -- 开始loopU型内环
-> e_loop:loop
->
-> -- 根据游标 当前指向一条数据
-> fetch emp_cur into l_empno,l_sal,l_bonus;
->
-> -- 当 游标的返回值为 1 时 退出 loop循环
-> if done = 1 then
-> leave e_loop;
-> end if;
->
-> -- 如果奖金为空加500，如果奖金为0，不加，其它情况下加1000
-> if l_bonus is null then
-> update emp set comm = l_add_bonus2 where empno = l_empno;
-> elseif l_bonus = 0 then
-> begin
-> end;
-> else
-> update emp set comm = l_add_bonus1 + comm where empno = l_empno;
-> end if;
->
-> end loop;
-> -- 关闭游标
-> close emp_cur;
-> end//
Query OK, 0 rows affected (0.00 sec)
mysql>
mysql> delimiter ;
mysql>
mysql>
mysql>
mysql> select * from emp;
+-------+--------+-----------+------+------------+---------+---------+--------+
| empno | ename | job | mgr | hiredate | sal | comm | deptno |
+-------+--------+-----------+------+------------+---------+---------+--------+
| 7369 | SMITH | CLERK | 7902 | 1980-12-17 | 800.00 | NULL | 20 |
| 7499 | ALLEN | SALESMAN | 7698 | 1981-02-20 | 1600.00 | 300.00 | 30 |
| 7521 | WARD | SALESMAN | 7698 | 1981-02-22 | 1250.00 | 500.00 | 30 |
| 7566 | JONES | MANAGER | 7839 | 1981-04-02 | 2975.00 | NULL | 20 |
| 7654 | MARTIN | SALESMAN | 7698 | 1981-09-28 | 1250.00 | 1400.00 | 30 |
| 7698 | BLAKE | MANAGER | 7839 | 1981-05-01 | 2850.00 | NULL | 30 |
| 7782 | CLARK | MANAGER | 7839 | 1981-06-09 | 2450.00 | NULL | 10 |
| 7788 | SCOTT | ANALYST | 7566 | 1987-06-13 | 3000.00 | NULL | 20 |
| 7839 | KING | PRESIDENT | NULL | 1981-11-17 | 5000.00 | NULL | 10 |
| 7844 | TURNER | SALESMAN | 7698 | 1981-09-08 | 1500.00 | 0.00 | 30 |
| 7876 | ADAMS | CLERK | 7788 | 1987-06-13 | 1100.00 | NULL | 20 |
| 7900 | JAMES | CLERK | 7698 | 1981-12-03 | 950.00 | NULL | 30 |
| 7902 | FORD | ANALYST | 7566 | 1981-12-03 | 3000.00 | NULL | 20 |
| 7934 | MILLER | CLERK | 7782 | 1982-01-23 | 1300.00 | NULL | 10 |
+-------+--------+-----------+------+------------+---------+---------+--------+
14 rows in set (0.00 sec)
mysql>
mysql> call test1();
Query OK, 0 rows affected (0.04 sec)
4 rows in set (0.00 sec)
mysql> select * from emp;
+-------+--------+-----------+------+------------+---------+---------+--------+
| empno | ename | job | mgr | hiredate | sal | comm | deptno |
+-------+--------+-----------+------+------------+---------+---------+--------+
| 7369 | SMITH | CLERK | 7902 | 1980-12-17 | 800.00 | 500.00 | 20 |
| 7499 | ALLEN | SALESMAN | 7698 | 1981-02-20 | 1600.00 | 1300.00 | 30 |
| 7521 | WARD | SALESMAN | 7698 | 1981-02-22 | 1250.00 | 1500.00 | 30 |
| 7566 | JONES | MANAGER | 7839 | 1981-04-02 | 2975.00 | 500.00 | 20 |
| 7654 | MARTIN | SALESMAN | 7698 | 1981-09-28 | 1250.00 | 2400.00 | 30 |
| 7698 | BLAKE | MANAGER | 7839 | 1981-05-01 | 2850.00 | 500.00 | 30 |
| 7782 | CLARK | MANAGER | 7839 | 1981-06-09 | 2450.00 | 500.00 | 10 |
| 7788 | SCOTT | ANALYST | 7566 | 1987-06-13 | 3000.00 | 500.00 | 20 |
| 7839 | KING | PRESIDENT | NULL | 1981-11-17 | 5000.00 | 500.00 | 10 |
| 7844 | TURNER | SALESMAN | 7698 | 1981-09-08 | 1500.00 | 0.00 | 30 |
| 7876 | ADAMS | CLERK | 7788 | 1987-06-13 | 1100.00 | 500.00 | 20 |
| 7900 | JAMES | CLERK | 7698 | 1981-12-03 | 950.00 | 500.00 | 30 |
| 7902 | FORD | ANALYST | 7566 | 1981-12-03 | 3000.00 | 500.00 | 20 |
| 7934 | MILLER | CLERK | 7782 | 1982-01-23 | 1300.00 | 500.00 | 10 |
+-------+--------+-----------+------+------------+---------+---------+--------+
14 rows in set (0.00 sec)
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