当我尝试选择和更新同桌MySQL允许误差MYSQL触发从选择和更新相同的表给出了错误#1241 - 操作数应包含1列(S)
error
#1241 - Operand should contain 1 column(s)
触发器是
DELIMITER $$
CREATE TRIGGER visitor_validation
BEFORE INSERT ON ratingsvisitors
FOR EACH ROW
BEGIN
SET @ifexists = (SELECT * FROM ratingcounttracks WHERE userid=New.vistorid AND likedate=New.likevalidation AND countfor=New.likeordislike);
IF (@ifexists = NULL) THEN
INSERT INTO ratingcounttracks(userid, likedate, clickcount,countfor) values (New.vistorid, New.likevalidation ,'1',New.likeordislike);
ELSE
UPDATE ratingcounttracks SET clickcount=clickcount+1 WHERE userid=New.vistorid AND likedate=New.likevalidation AND countfor=New.likeordislike;
END IF;
END$$
你所试图做的是叫做* UPSERT *。您可能想了解更多,因为有不同的方法。在这个网站上有关于MySQL的upsert的问题。你可以从[这一个]开始(http://stackoverflow.com/questions/1218905/how-do-i-update-if-exists-insert-if-not-aka-upsert-or-merge-in-mysql “如果存在,我如何更新?如果不是(在MySQL中插入或插入)?”),然后按照* Linked *部分中的说明进行更新。 –