MySQL批量Insert应用ON DUPLICATE KEY UPDATE

也不清楚是设计的问题,还是实现的问题.
总之最后到我这里,是一个很奇怪的需求.

award_credit_room这个表,存放用户送礼的记录
award_credit 是用户送礼产生的积分记录

award_credit_room的数据经过汇总之后,需要批量Insert到award_credit表,
如果没有记录,则Insert,存在记录则Update

使用MySQL自定义变量,实现 insert..select...ON DUPLICATE KEY UPDATE

该功能使用如下SQL

set @a:=0;
set @b:=0;
insert into award_credit ( credits, vvid, CreditsTotal )
select @a:=sum(CreditChange) ,VVID,sum(CreditChange) 
from award_credit_room r
where awardActId = 23 and Status = 2 group by VVID
ON DUPLICATE KEY UPDATE credits = credits + @a, creditsTotal = creditsTotal +@a;

在执行之前的汇总查询结果
select @a:=sum(CreditChange) ,VVID,sum(CreditChange) 
from award_credit_room r
where awardActId = 23 and Status = 2 group by VVID

在SQL执行之前的award_credit表数据

在SQL执行之后的award_credit表数据

在实验的过程中,有一个优化的想法,既然两个字段都是sum聚合,能不能使用自定义变量计算一次呢,
实际上是行不通的,自定义变量的执行顺序和变量的位置并不是严格固定的.

但是也有变通的方法
set @a:=0;
 insert into award_credit ( credits, vvid, CreditsTotal )
 select @a:=s,vvid,s from
 (
    select sum(CreditChange) s,VVID  from award_credit_room r where awardActId = 23 and Status = 2 group by VVID
 ) t1
 ON DUPLICATE KEY UPDATE credits = credits + @a, creditsTotal = creditsTotal +@a;