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[英]create trigger on update to insert old values into other table in MYSQL
[英]MYSQL Trigger - update values in table from other table before insert
我正在尝试在从另一个表插入之前更新值-这是我所拥有的:
2桌
hbrpg_geo{
...
id INT //id that needs to be written into hbrpg_person
zip VARCHAR(10) //contains postcode
...
}
hbrpg_person{
...
fk_postcode // initially it's filled with UK postcode - but trigger should change value to id of hbrpg_geo of matching postcode (hbrpg_geo.zip).
...
}
触发:
...
BEGIN
DECLARE NP_VAR integer;
DECLARE OP_VAR TEXT;
SET OP_VAR = NEW.fk_postcode;
SET TE_VAR = OP_VAR;
SELECT hbrpg_geo.id INTO NP_VAR FROM hbrpg_geo WHERE hbrpg_geo.zip = OP_VAR;
SET NEW.fk_postcode = NP_VAR;
END
一切似乎都与以下工作不同:
SET OP_VAR = NEW.fk_postcode;
如果将NEW.fk_postcode替换为带引号的有效英国邮政编码(即:“ W1 3XX”),它将正常工作,并且触发器将hkpg_geo表的ID替换为字段fk_postcode。
我做错了什么? 如何将NEW.fk_postcode的值分配给刚刚声明的变量?
您具有分配顺序:
SET OP_VAR = NEW.fk_postcode;
. . .
SET NEW.fk_postcode = NP_VAR;
列new.fk_postcode
具有相同的类型。 但是这些列分别是text
和integer
。
您需要修复类型不兼容。 我的猜测是fk_postcode
实际上是一个整数,并且与值(将是字符串)分开。
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