Question

Hello目前我的触发器更新了表更新，我需要将其更改为仅在特定列更改时触发。

代码：在things

上更新后创建触发器资金

for each row
begin
UPDATE `current` c 
INNER JOIN things    t ON c.id2 = t.id2
INNER JOIN dude_base d ON d.id1 = c.is1
SET c.`curr_cash` = t.thing_cost * d.salary / 100;
end;
$$

当需要更新“thing_cost”时，我需要进行更改，以便启用。

@edit 我必须更新curr_cash并且事情成本总是不同的值，我无法比较它们，它们将永远是不同的。

当我使用

时

if NEW.things_cost <> OLD.things_cost

我收到以下错误：

#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 10

@edit

create trigger wys_sk_b after update on `dude_base`
for each row
begin
if NEW.salary <> OLD.salary
then
UPDATE `current` s 
INNER JOIN things u ON s.id_thing = u.id_thing 
INNER JOIN dude_base b ON b.id = s.id
SET s.`curr_cash` = u.thing_cost * b.salary/ 100;
end if;
$$

Answer 1

delimiter $$
create trigger wys_sk_b after update on `dude_base`
for each row
begin
  if NEW.salary <> OLD.salary
  then
    UPDATE `current` s 
    INNER JOIN things u ON s.id_thing = u.id_thing 
    INNER JOIN dude_base b ON b.id = s.id
    SET s.`curr_cash` = u.thing_cost * b.salary/ 100;
  end if;
end;
$$

Answer 2

试试此代码......

**create table sales** (orderno INT, sale INT,empsalary int, ts TIMESTAMP);

**create table history** (updated varchar(20), oldvalue INT,newvalue INT);

INSERT INTO **sales** (orderno,sale,empsalary) VALUES(1,700,7000);

INSERT INTO **sales** (orderno,sale,empsalary) VALUES(2,800,8000);

INSERT INTO **sales** (orderno,sale,empsalary) VALUES(3,900,9000);


DROP TRIGGER test.instrigger;

DELIMITER ///

CREATE TRIGGER test.instrigger AFTER UPDATE ON sales
FOR EACH ROW

BEGIN

    IF NEW.sale <> OLD.sale THEN  
        INSERT INTO history (updated, oldvalue, newvalue) VALUES('sale', OLD.sale,NEW.sale);

    END IF;
    IF NEW.empsalary <> OLD.empsalary THEN  
        INSERT INTO history (updated, oldvalue, newvalue) VALUES('empsalary', OLD.empsalary,NEW.empsalary);
    END IF;
END;

///

DELIMITER;

列更改时触发更新

2 个答案: