MySQL数据库update语句使用详解

update Player as a ,PlayerSet as b
set a.role_id=b.set_value 
where a.role_id=b.set_key

update RoleSet
set_key=(SELECT name FROM Player where id = RoleSet.set_value);

Error Code: 1055. Expression #2 of SELECT list is not in GROUP BY clause and contains nonaggregated column 'xxxxxxx' which is not functionally dependent on columns in GROUP BY clause; this is incompatible with sql_mode=only_full_group_by
（中文意思大概是：不能对同一张表进行同时读写）

set @i:=1;
update Group 
SET name=CONCAT(name,'_', (@i:=@i+1))
where name in
(
SELECT a.GroupName
from
(
        SELECT name  as GroupName
        FROM Group 
        GROUP BY name 
        HAVING count(*) > 1
) as a
);