MySQL SELECT同时UPDATE同一张表问题发生及解决

复制代码 代码如下:

create table apples(variety char(10) primary key, price int);
insert into apples values('fuji', 5), ('gala', 6);
update apples
set price = (select price from apples where variety = 'gala')
where variety = 'fuji';

复制代码 代码如下:

update apples
set price = (
select price from (
select * from apples
) as x
where variety = 'gala')
where variety = 'fuji';