Question

我正在尝试使用游标在存储过程中编写动态游标，如建议的here。但是当我尝试从光标中获取数据时，它似乎是空白的并且不执行循环内部的内容。我通过在循环内打印来证实这一点。

这是存储过程：

DELIMITER //
DROP PROCEDURE IF EXISTS `rd22` ;
CREATE PROCEDURE rd22(IN unitList varchar(100), OUT dur INT)
 BEGIN
     DECLARE c, done INT;
     DECLARE cursor_end CONDITION FOR SQLSTATE '02000'; 
     DECLARE v_column_val VARCHAR(50); 
     DECLARE cur_table CURSOR FOR select * from abet_view;
     DECLARE CONTINUE HANDLER FOR cursor_end SET done = 1; 

set @ul = unitList;
set @qry = concat("CREATE VIEW  abet_view as SELECT abet.duration ",
 "from active_begin_end_times as abet INNER JOIN alarm_sources as a ON a.id = abet.alarm_source ",
 "and a.unit IN(",@ul,") WHERE abet.begin_timestamp = 1395874800000");    

DROP VIEW abet_view; 
prepare stmt from @qry;
execute stmt;   

OPEN cur_table; 
 FETCH cur_table INTO v_column_val; 
 WHILE done = 0 DO 
    SET c = c + v_column_val;
    FETCH cur_table INTO v_column_val; 
 END WHILE; 

 CLOSE cur_table; 

    SET dur = @c;  
END//
DELIMITER ;

SET @val = '1,2,3';
CALL rd22(@val, @dur);

我是第一次编写存储过程，所以任何帮助都是值得的。

干杯！

动态游标使用mysql中的视图

0 个答案: