a表:
id (key)
deviceid
devicename
brand
b表:
id (key)
deviceid(key)联合主键
devicename
brand
请问如何才能做到到b表插入deviceid时，如果a.deviceid=b.deviceid则更新b.devicename and b.brand
我的写法是
BEGIN
UPDATE b SET
devicename = new.devicename,
brand = new.brand
WHERE deviceid = (SELECT deviceid FROM a WHERE brand = new.brand and devicename = new.devicename and brand = new.brand );
但是这样不对，请问大神改怎么做？
http://blog.csdn.net/lovelichao12/article/details/76680214
WHERE deviceid = () “等号绝对出错”
关闭问题提高C币悬赏