Question

我有一个存储过程，它将带有排名的视图中的行插入临时表。

在运行插入值的游标循环之前创建临时表，在循环完成后创建SELECT。

然而当我CALL medianMessagesPerWeek（）;我得到一个“错误代码：1329没有数据 - 提取，选择或处理零行。”

如果我将表创建为MYISAM表，我可以手动选择表并确认已插入数据，但存储的proc仍然不会给我任何内容。

我在这里错过了什么吗？

DELIMITER $$

USE `yongopal_metrics`$$

DROP PROCEDURE IF EXISTS `medianMessagesPerWeek`$$

CREATE DEFINER=`root`@`localhost` PROCEDURE `medianMessagesPerWeek`()
BEGIN
    DECLARE done INT DEFAULT FALSE;
    DECLARE tempJoinWeek, tempActiveWeek, rank INT DEFAULT 0;
    DECLARE joinWeek, activeWeek, memberNo, messages INT;
    DECLARE cur CURSOR FOR SELECT * FROM cohortMessagesPerMemberPerWeek;

    DROP TEMPORARY TABLE IF EXISTS medianMessagesPerWeek;
    CREATE TEMPORARY TABLE medianMessagesPerWeek
    (
        joinWeek INT,
        activeWeek INT,
        memberNo INT,
        messages INT,
        rank INT
    ) ENGINE=MEMORY;    

    OPEN cur;

    read_loop: LOOP
        FETCH cur INTO joinWeek, activeWeek, memberNo, messages;
        IF done THEN
            LEAVE read_loop;
        END IF;

        IF tempJoinWeek = joinWeek AND tempActiveWeek = activeWeek THEN
            SET rank = rank + 1;
        ELSE
            SET tempJoinWeek = joinWeek;
            SET tempActiveWeek = activeWeek;
            SET rank = 1;
        END IF;
        INSERT INTO medianMessagesPerWeek VALUES (joinWeek, activeWeek, memberNo, messages, rank);
    END LOOP;

    CLOSE cur;

    SELECT * FROM medianMessagesPerWeek;
    DROP TEMPORARY TABLE IF EXISTS medianMessagesPerWeek;
    END$$

DELIMITER ;

修改

这是cohortMessagesPerMemberPerWeek的样子

DELIMITER $$

USE `yongopal_metrics`$$

DROP VIEW IF EXISTS `cohortMessagesPerMemberPerWeek`$$

CREATE ALGORITHM=UNDEFINED DEFINER=`root`@`localhost` SQL SECURITY DEFINER VIEW `cohortMessagesPerMemberPerWeek` AS 
SELECT
  WEEK(`m`.`regDatetime`,0) AS `joinWeek`,
  WEEK(`cd`.`sendDate`,0) AS `activeWeek`,
  `m`.`memberNo` AS `memberNo`,
  COUNT(0)       AS `messages`
FROM (`yongopal`.`chatData` `cd`
   JOIN `yongopal`.`members` `m`
     ON ((`cd`.`sender` = `m`.`memberNo`)))
GROUP BY WEEK(`m`.`regDatetime`,0),WEEK(`cd`.`sendDate`,0),`m`.`memberNo`
ORDER BY WEEK(`m`.`regDatetime`,0),WEEK(`cd`.`sendDate`,0)$$

DELIMITER ;

Answer 1

您的cur光标似乎缺少not found handler。当done语句不再返回任何行（因此您已到达游标声明返回的数据集的末尾）时，必须将fetch布尔值设置为true。

尝试一下：

DELIMITER $$

USE `yongopal_metrics`$$

DROP PROCEDURE IF EXISTS `medianMessagesPerWeek`$$

CREATE DEFINER=`root`@`localhost` PROCEDURE `medianMessagesPerWeek`()
BEGIN
    DECLARE done INT DEFAULT FALSE;
    DECLARE tempJoinWeek, tempActiveWeek, rank INT DEFAULT 0;
    DECLARE joinWeek, activeWeek, memberNo, messages INT;
    DECLARE cur CURSOR FOR SELECT * FROM cohortMessagesPerMemberPerWeek;

    declare continue handler for not found set done := true; 

    DROP TEMPORARY TABLE IF EXISTS medianMessagesPerWeek;
    CREATE TEMPORARY TABLE medianMessagesPerWeek
    (
        joinWeek INT,
        activeWeek INT,
        memberNo INT,
        messages INT,
        rank INT
    ) ENGINE=MEMORY;    

    OPEN cur;

    read_loop: LOOP
        FETCH cur INTO joinWeek, activeWeek, memberNo, messages;
        IF done THEN
            LEAVE read_loop;
        END IF;

        IF tempJoinWeek = joinWeek AND tempActiveWeek = activeWeek THEN
            SET rank = rank + 1;
        ELSE
            SET tempJoinWeek = joinWeek;
            SET tempActiveWeek = activeWeek;
            SET rank = 1;
        END IF;
        INSERT INTO medianMessagesPerWeek VALUES (joinWeek, activeWeek, memberNo, messages, rank);
    END LOOP;

    CLOSE cur;

    SELECT * FROM medianMessagesPerWeek;
    DROP TEMPORARY TABLE IF EXISTS medianMessagesPerWeek;
    END$$

DELIMITER ;

临时表不返回MySQL存储过程中的结果集

1 个答案: