创建一个MySQL存储过程,该过程使用游标从表中获取行?
以下是一个存储过程,该存储过程从具有以下数据的表“student_info”的名称列中获取记录-
mysql> Select * from Student_info; +-----+---------+------------+------------+ | id | Name | Address | Subject | +-----+---------+------------+------------+ | 101 | YashPal | Amritsar | History | | 105 | Gaurav | Chandigarh | Literature | | 125 | Raman | Shimla | Computers | | 127 | Ram | Jhansi | Computers | +-----+---------+------------+------------+ 4 rows in set (0.00 sec) mysql> Delimiter // mysql> CREATE PROCEDURE cursor_defined(OUT val VARCHAR(20)) -> BEGIN -> DECLARE a,b VARCHAR(20); -> DECLARE cur_1 CURSOR for SELECT Name from student_info; -> DECLARE CONTINUE HANDLER FOR NOT FOUND -> SET b = 1; -> OPEN CUR_1; -> REPEAT -> FETCH CUR_1 INTO a; -> UNTIL b = 1 -> END REPEAT; -> CLOSE CUR_1; -> SET val = a; -> END// mysql> Delimiter ; mysql> Call cursor_defined2(@val); mysql> Select @val; +------+ | @val | +------+ | Ram | +------+ 1 row in set (0.00 sec)
从上面的结果集中,我们可以看到val参数的值为'Ram',因为它是'Name'列的最后一个值。