MySQL动态游标

MySQL本身是不支持动态游标的，但可以通过（准备语句+视图+静态游标）的方法来近似实现。

一个简单示例：

-- 建立测试表和数据
create table webuser (username varchar(10));
insert into webuser values ('a1'),('a2'),('a3'),('b1'),('b2'),('b3');
commit;

-- 建立存储过程
drop procedure if exists dynamic_cursor;
delimiter //
CREATE PROCEDURE dynamic_cursor (IN p_name varchar(10))
BEGIN 
    DECLARE done INT DEFAULT 0;
    DECLARE v_username varchar(10);
    DECLARE cur CURSOR for( SELECT username from webuser_view);
    DECLARE CONTINUE HANDLER FOR NOT FOUND SET done = 1;

    DROP VIEW IF EXISTS webuser_view;

    SET @sqlstr = "CREATE VIEW webuser_view as ";
    SET @sqlstr = CONCAT(@sqlstr , "SELECT username FROM webuser WHERE username like '", p_name,"%'");

    PREPARE stmt FROM @sqlstr;
    EXECUTE stmt;
    DEALLOCATE PREPARE stmt;

    OPEN cur;
    f_loop:LOOP 
    FETCH cur INTO v_username;
	IF done THEN 
		LEAVE f_loop;  
	END IF;
 	SELECT v_username;    
    END LOOP f_loop;
    CLOSE cur;
END;
//
delimiter ;

-- 测试
call dynamic_cursor('a');