以下代码中的错误似乎是啥？

Posted 2023-05-09

【中文标题】以下代码中的错误似乎是啥？

【英文标题】：What seems to be the error here in the below code?以下代码中的错误似乎是什么？

【发布时间】：2021-04-12 17:42:52

【问题描述】：

错误代码：2014 命令不同步；你现在不能运行这个命令

平台 - My SQL Workbench

DELIMITER//
DROP PROCEDURE IF EXISTS must_watch_movies;
CREATE PROCEDURE
must_watch_movies ()
BEGIN DECLARE mTitle
VARCHAR (45);
     DECLARE mDistributor VARCHAR (45);
     DECLARE mRelease datetime;
     DECLARE result VARCHAR (1000);
     DECLARE no_records INTEGER DEFAULT FALSE;
     DECLARE cursor_movies CURSOR FOR
       SELECT title, Distributor, year (release_date)
     FROM movies WHERE gross > 200000000 ORDER BY title;

     DECLARE CONTINUE HANDLER FOR NOT FOUND SET SET no_records = TRUE;

     OPEN cursor_movies;
     WHILE no_records = FALSE DO
       FETCH cursor_movies INTO mTitle, mDistributor, mRelease;
     SET result =
       CONCAT ("'", mTitle, "','" mDistributor, "','" mRelease, "|");
     END WHILE;
     CLOSE cursor_movies;
     SELECT result AS "Output";
END//
  DELIMITER;

调用 must_watch_movies();

声明的值与表中实际列值的数据类型相匹配。 比如mTitle和title是同一个类型

【参考方案1】：

您的代码中有一些错误

在处理处理程序时使用双重 SET

如果你想要所有电影，你必须连接结果。

输出一定要复杂一些，但我把它留给你

CREATE TABLE movies (title varchar(10),Distributor varchar(19), release_date date,gross BIGINT)

INSERT INTO movies VALUES('text1','text2', NOW(),200000001),('text3','text4', NOW(),200000001),('text5','text6', NOW(),200000001)

CREATE PROCEDURE
must_watch_movies ()
BEGIN DECLARE mTitle
VARCHAR (45);
     DECLARE mDistributor VARCHAR (45);
     DECLARE mRelease INT;
     DECLARE result VARCHAR (1000) DEFAULT "";
     DECLARE no_records INTEGER DEFAULT FALSE;
     DECLARE cursor_movies CURSOR FOR
       SELECT title, Distributor, year (release_date)
     FROM movies WHERE gross > 200000000 ORDER BY title;

     DECLARE CONTINUE HANDLER FOR NOT FOUND SET  no_records = TRUE;

     OPEN cursor_movies;
     WHILE no_records = FALSE DO
       FETCH cursor_movies INTO mTitle, mDistributor, mRelease;
     SET result = CONCAT (result,"'", mTitle, "','", mDistributor, "','", mRelease, "|");
     END WHILE;
     CLOSE cursor_movies;
     SELECT result AS "Output";
END

CALL must_watch_movies()

|输出 | | :------------------------------------------------- -------------------------------------------------- | | 'text1','text2','2021|'text3','text4','2021|'text5','text6','2021|'text5','text6','2021| | ✓

db小提琴here

【讨论】：

谢谢！我让它运行，但我没有得到任何输出，或者我应该说我得到 null

当您看到该程序有效时，请更改 dbfiddle 并发布一个 lonk ，以便我可以检查它并请复制所有内容，尤其是结果的默认值

谢谢。事实证明，百万是 1 对 100 万，2 对 200 万，依此类推。终于成功了

@albion 请不要忘记accept it