Query : CREATE TRIGGER Update_p_count_Trigger AFTER INSERT ON book FOR EACH ROW UPDATE press SET p_count = + book.Quantity WHERE p_i... Error Code : 1235 This version of MySQL doesn't yet support 'multiple triggers with the same action time and event for one table' Execution Time : 00:00:00:000 Transfer Time : 00:00:00:000 Total Time : 00:00:00:000\

这个错误提示是因为MySQL版本不支持在同一表上创建多个相同操作时间和事件的触发器。这意味着您不能为同一个表的同一个事件和操作时间创建多个触发器。

解决此问题的方法是合并所有需要的逻辑到一个触发器中。例如，在您的情况下，您可以将两个触发器合并为一个触发器，如下所示：

CREATE TRIGGER Update_p_count_Trigger
AFTER INSERT ON book
FOR EACH ROW
    UPDATE press SET p_count = p_count + NEW.Quantity WHERE p_id = NEW.p_id;

这个触发器将在每次插入新的书籍时被触发，并且会更新出版社表中的p_count列。请注意，我们使用NEW关键字来引用插入的新行数据。我们还使用WHERE子句来指定要更新的出版社。

希望这可以帮助您解决问题。

相关问题

CREATE TRIGGER check_room_availability_trigger BEFORE INSERT ON has_BookingRel FOR EACH ROW BEGIN DECLARE available_rooms INT; SELECT room_num - IFNULL(SUM(booked_quantity), 0) INTO available_rooms FROM room_types LEFT JOIN has_BookingRel ON room_types.id = has_BookingRel.room_type_id WHERE room_types.id = NEW.room_type_id; GROUP BY room_types.id, room_types.name, room_types.price; IF available_rooms < NEW.booked_quantity THEN SIGNAL SQLSTATE “45000” SET MESSAGE_TEXT = ‘房间数量不足’; END IF; END;所以这个触发器该怎样改：1140 - In aggregated query without GROUP BY, expression #1 of SELECT list contains nonaggregated column 'h.room_types.room_num'; this is incompatible with sql_mode=only_full_group_by

这个错误是由于 MySQL 5.7.5 版本之后默认启用了 only_full_group_by 模式，而在该模式下，如果 SELECT 语句中的列没有在 GROUP BY 子句中出现，那么 MySQL 将会报错。在你的触发器代码中，SELECT 语句中的 room_num 列没有在 GROUP BY 子句中出现，因此会报这个错误。你需要将这个 SELECT 语句中的列改为聚合函数，比如使用 SUM()。

改为以下代码：

CREATE TRIGGER check_room_availability_trigger BEFORE INSERT ON has_BookingRel FOR EACH ROW 
BEGIN 
    DECLARE available_rooms INT; 
    SELECT room_types.room_num - IFNULL(SUM(has_BookingRel.booked_quantity), 0) INTO available_rooms 
    FROM room_types 
    LEFT JOIN has_BookingRel ON room_types.id = has_BookingRel.room_type_id 
    WHERE room_types.id = NEW.room_type_id 
    GROUP BY room_types.id, room_types.name, room_types.price, room_types.room_num; 
    IF available_rooms < NEW.booked_quantity THEN 
        SIGNAL SQLSTATE “45000” SET MESSAGE_TEXT = ‘房间数量不足’; 
    END IF; 
END;

这样改动后，应该就可以避免这个错误了。

$check_query += " FOR UPDATE";

This statement is used in SQL to lock the selected rows for update until the transaction is complete. It ensures that no other transaction can modify the selected rows until the current transaction is finished. The "FOR UPDATE" statement is commonly used in scenarios where multiple users are accessing the same data simultaneously, such as in a database application, to prevent data inconsistency and conflicts.