如何从mysql5触发器中的选择查询中获取值? [英] how to get value from select query in trigger in mysql5?

问题描述

如何从触发器中的选择查询中获取值并将该值插入表中?

How to get value from select query in trigger and insert that value in table?

推荐答案

对于 INSERT 触发器查询，您将使用对象 NEW
对于 UPDATE Trigger 查询，您将使用对象 OLD 和 NEW
对于 DELETE 触发器查询，您将使用对象 OLD

For an INSERT Trigger query you would use the object NEW
For an UPDATE Trigger query you would use the object OLD and NEW
For a DELETE Trigger query you would use the object OLD

示例 1:如果您运行 INSERT INTO mytable (num) VALUES (10);
在 INSERT 触发器中，您将该列引用为 NEW.num (10);

Example 1 : iF you ran INSERT INTO mytable (num) VALUES (10);
In the INSERT trigger, you reference the column as NEW.num (10);

示例 2:如果您运行 UPDATE mytable SET num = 41 WHERE num = 10;
在 UPDATE 触发器中，您引用 OLD.num (10) 和 NEW.num (41)

Example 2 : iF you ran UPDATE mytable SET num = 41 WHERE num = 10;
In the UPDATE trigger, you reference OLD.num (10) and NEW.num (41)

示例 3:如果您运行 DELETE mytable num = 104;
在 DELETE 触发器中，您引用了 OLD.num (104)

Example 3 : iF you ran DELETE mytable num = 104;
In the DELETE trigger, you reference OLD.num (104)

使用这样的东西:

DELIMITER $$

create trigger my_trigger
AFTER UPDATE on my_update_table
for each row
begin

    DECLARE P1,P2 VARCHAR(50);

    SELECT PRICENAME INTO P1 FROM PRICEIES WHERE PRICEID=OLD.PRICEID;
    SELECT PRICENAME INTO P2 FROM PRICEIES WHERE PRICEID=NEW.PRICEID;
    INSERT INTO AUDITLOG(OLDVALUE, NEWVALUE) VALUES (P1,P2);

end $$

DELIMITER ;

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