left join+group by语句性能优化

一、背景

需求：求【昨日触达】、【本周拜访】、【本月活动数】。
背景：三个维度的数据都按日统计在一张表里。
首先想到的就是left join +group by。

1.1 优化前语句

select
	user_id,
	user_name,
	org_id,
	org_name,
	sum(reach_num) dayReachNum,
	sum(visit_num) weekVisitNum,
	sum(activity_num) mouthActivityNum
from
	(
	select
		srsm.user_id,
		srsm.user_name,
		srsm.org_id,
		srsm.org_name,
		srsd.reach_num,
		srsw.visit_num,
		srsm.activity_num
	from
		standard_reach_statistics srsm
	left join standard_reach_statistics srsd on
		srsd.user_id = srsm.user_id
		and srsd.statistical_date between '2024-01-01' and '2024-01-01'
	left join standard_reach_statistics srsw on
		srsm.user_id = srsw.user_id
		and srsw.statistical_date between '2024-01-01' and '2024-01-07'
	where
		srsm.statistical_date between '2024-01-01' and '2024-01-31'
                   
                   ) tt
group by
	user_id,
	user_name,
	org_id,
	org_name

分析这条语句存在的问题：

二、优化后语句

思路：

1. 解决后两个left join表数据过大问题：可以先把后两个left join语句sum出来，在left join；

select
	srsm.user_id,
	reach_num_sum dayReachNum,
	visit_num_sum weekVisitNum ,
	sum(srsm.activity_num) mouthActivityNum
from
	standard_reach_statistics srsm
left join (
	select
		srsd.user_id,
		sum(srsd.reach_num) reach_num_sum
	from
		standard_reach_statistics srsd
	where
		srsd.statistical_date between '2024-01-01' and '2024-01-01'
	group by
		user_id ) sum_day on
	srsm.user_id = sum_day.user_id
left join (
	select
		srsw.user_id,
		sum(srsw.visit_num)visit_num_sum
	from
		standard_reach_statistics srsw
	where
		srsw.statistical_date between '2024-01-01' and '2024-01-07'
	group by
		user_id ) sum_month on
	srsm.user_id = sum_month.user_id
where
	srsm.statistical_date between '2024-01-01' and '2024-01-31'
group by
	user_id;

优化后效率由原来的50s，变成了86ms，效率提升明显。