MySQL - 列的条件连接

Question

我有以下查询:

select ad_st_id_state, count(distinct id_visit) as Visits
from sf_visit
join vr_users on vi_us_id_user = sus_us_id_user
join sf_pdv on vi_pdv_id_pdv = id_pdv
join sf_address on pdv_ad_id_address = id_address

group by ad_st_id_state
order by ad_st_id_state

我也有这个:

select ad_st_id_state, count(distinct id_visit) as DoneVisits
from sf_visit
join vr_users on vi_us_id_user = sus_us_id_user
join sf_pdv on vi_pdv_id_pdv = id_pdv
join sf_address on pdv_ad_id_address = id_address
join sf_visit_file_time on id_visit = vft_vi_id_visit /* Another join has been added */

group by ad_st_id_state
order by ad_st_id_state

如您所见，除了一个额外的 join 语句外，查询几乎是相同的。 这两个查询都返回我需要的正确值，但我需要将它们连接到一个表中，所以我这样做:

select fffuuu.ad_st_id_state, count(distinct id_visit) as Visitas, fffuuu.doneVisits
from sf_visit
join vr_users on vi_us_id_user = sus_us_id_user
join sf_pdv on vi_pdv_id_pdv = id_pdv
join sf_address on pdv_ad_id_address = id_address

join (
select ad_st_id_state, count(distinct id_visit) as doneVisits
from sf_visit
join vr_users on vi_us_id_user = sus_us_id_user
join sf_pdv on vi_pdv_id_pdv = id_pdv
join sf_address on pdv_ad_id_address = id_address
join sf_visit_file_time on id_visit = vft_vi_id_visit

group by ad_st_id_state
order by ad_st_id_state
) as fffuuu on sf_address.ad_st_id_state = fffuuu.ad_st_id_state

group by ad_st_id_state
order by ad_st_id_state

或者换句话说，我将第一个查询与第二个查询连接为一个子查询。结果集很好而且正确，但花费的时间太长，所以我在另一个系统中超时，这个查询正在运行。每个查询独立运行得很快，但加入它们对我的需求来说太慢了......

我想知道是否有办法优化这个，我在想是否有一些连接条件语句或其他东西。我搜索了信息，但我没有任何运气。我在想:

select ad_st_id_state, count(distinct id_visit) as Visits, if(@someVariable := true) as DoneVisits
from sf_visit
join vr_users on vi_us_id_user = sus_us_id_user
join sf_pdv on vi_pdv_id_pdv = id_pdv
join sf_address on pdv_ad_id_address = id_address
if (@someVariable == true) then join sf_visit_file_time on id_visit = vft_vi_id_visit

group by ad_st_id_state
order by ad_st_id_state

或者类似的东西。我该如何优化它？

Answer 1

您能否在计数中使用 sf_visit_file_time 的外连接和 case 语句？显然，我在本地没有您的架构，但类似于:

select ad_st_id_state, 
   count(distinct id_visit) as Visits,
   count(distinct case when vft_vi_id_visit is not null then id_visit end) as DoneVisits
from sf_visit
join vr_users on vi_us_id_user = sus_us_id_user
join sf_pdv on vi_pdv_id_pdv = id_pdv
join sf_address on pdv_ad_id_address = id_address
left join sf_visit_file_time on id_visit = vft_vi_id_visit
group by ad_st_id_state
order by ad_st_id_state