how to write trigger with multiple condition in mysql

问题

I had made two tables with the following fields:

TABLE 1: "demo"
FIELD: "demoid"
FIELD: "cpid"
FIELD: "status"     


TABLE 2: "sample"
FIELD: "id"
FIELD: "conid"    
FIELD: "statussample"
FIELD: "date"

I want to update the status whenever the sample table field statussample gets changed. The condition would be

1) `demoid` and `id` would be same and `cpid` and `conid` would be same.(if more than one values comes i want the last inserted value of  `sample` using the field `date`)

How to do that?I had stuck with this..new to Trigger format

回答1:

DELIMITER //

CREATE TRIGGER sample_after_update
AFTER UPDATE
    ON sample FOR EACH ROW

BEGIN

   UPDATE demo
   SET demoid = NEW.id,
       cpid   = NEW.conid

END; //
DELIMITER;

来源：https://stackoverflow.com/questions/38745441/how-to-write-trigger-with-multiple-condition-in-mysql