在 MySQL 中创建预定事件

Question

我在名为 fouras 的 MySQL 数据库中提供了 table 个名称：

mysql> desc offer;
+------------------------+---------------+------+-----+---------+----------------+
| Field                  | Type          | Null | Key | Default | Extra          |
+------------------------+---------------+------+-----+---------+----------------+
| id                     | bigint(20)    | NO   | PRI | NULL    | auto_increment |
| description            | varchar(5000) | NO   |     | NULL    |                |
| end_date               | date          | NO   |     | NULL    |                |
| is_accepted            | bit(1)        | NO   |     | NULL    |                |
| is_active              | bit(1)        | NO   |     | NULL    |                |
| is_draft               | bit(1)        | NO   |     | NULL    |                |
| is_processed           | bit(1)        | NO   |     | NULL    |                |
| is_removed             | bit(1)        | NO   |     | NULL    |                |
| max_reservation_number | int(11)       | NO   |     | NULL    |                |
| promotion_first_param  | varchar(255)  | YES  |     | NULL    |                |
| promotion_product      | varchar(255)  | YES  |     | NULL    |                |
| promotion_second_param | varchar(255)  | YES  |     | NULL    |                |
| promotion_type         | varchar(255)  | NO   |     | NULL    |                |
| publish_date           | date          | YES  |     | NULL    |                |
| remove_time_stamp      | bigint(20)    | YES  |     | NULL    |                |
| start_date             | date          | NO   |     | NULL    |                |
| title                  | varchar(255)  | NO   |     | NULL    |                |
| views_number           | int(11)       | YES  |     | NULL    |                |
| local_business         | bigint(20)    | YES  | MUL | NULL    |                |
+------------------------+---------------+------+-----+---------+----------------+
19 rows in set (0.00 sec)

现在，我想定期检查报价是否已过期（end_date > 今天），为此我正在尝试使用 MySQL 预定事件：

CREATE EVENT IF NOT EXISTS check_expired_offers
    ON SCHEDULE EVERY 10 MINUTE
    DO
        BEGIN
            DECLARE id INT;
            DECLARE end_date DATE;
            DECLARE offer_cursor CURSOR FOR SELECT id, end_date FROM fouras.offer;

            OPEN offer_sursor;
            offer_loop: LOOP
                FETCH offer_cursor into id, end_date;
                IF end_date < NOW() THEN 
                    UPDATE fouras.offer set is_active = false;  
                END IF;

            END LOOP
END;

但是 MySQL 在我尝试添加此事件时抛出错误：

Error Code: 1064. You have an error in your SQL syntax; check the manual that corresponds to your MySQL server version for the right syntax to use near '' at line 5    0,127 sec

Answer 1

错误是关于分隔符的，这个tutorial对我帮助很大

Answer 2

============================

发现分隔符问题。

============================

这是修改后的 event:

DELIMITER $$
CREATE EVENT IF NOT EXISTS check_expired_offers
    ON SCHEDULE EVERY 10 MINUTE
    DO
        BEGIN
            DECLARE finished INTEGER DEFAULT 0;
            DECLARE id INT;
            DECLARE end_date DATE;
            DECLARE offer_cursor CURSOR FOR SELECT id, end_date FROM fouras.offer;
                        DECLARE CONTINUE HANDLER FOR NOT FOUND SET finished = 1;

            OPEN offer_cursor;
            offer_loop: 
                        LOOP
                FETCH offer_cursor into id, end_date;
                IF finished = 1 THEN 
                                    LEAVE offer_loop;
                                END IF;
                                IF end_date < NOW() THEN 
                    UPDATE fouras.offer set is_active = false;  
                END IF;

            END LOOP ;
END $$
DELIMITER ;

Learn delimiters in MySQL

注意： 我也在那里使用了一个名为 finished.

的变量

其中finished是一个变量，表示游标已经到达结果集的末尾。请注意，处理程序声明必须出现在存储程序中的变量和游标声明之后。

下图说明了 MySQL 游标的工作原理。

在 MySQL 中创建预定事件

Creating a scheduled event in MySQL

mysql

sql

mysql-workbench

mysql-error-1064

mysql-event

发现分隔符问题。