[Err] 1093 - You can't specify target table 'good' for update in FROM clause

Question

update good set goods_price=((select goods_price from good where good_id=4)+100) WHERE good_id=4;mysql 上写这句话报： [Err] 1093 - You can't specify target table 'good' for update in FROM clause如何修改mysql语句

Answer 1

update good set goods_price=goods_price+100  WHERE good_id=4;

这样可以不？

Answer 2

为什么要这样写？