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?