为子查询优化Postgresql查询

Question

我对Postgres来说还很陌生，这可能是一个新手问题。如何改善此查询？

三个表，campaigns 1-> Mthreads1-> M messages。我有广告系列ID，我希望所有线程的所有相关消息的总数分别为opens，clicks和replies，其中opens和clicks在名为extra的JSONB字段中， messages和答复是具有messages列的"direction"='received'。

select "threads".*, 
count("messages"."extra"->'opens') as opens, 
count("messages"."extra"->'clicks') as clicks, 
(
    select count("messages"."id")
    from "messages" 
    where "messages"."thread_id" = "threads"."id" 
    and "messages"."direction"='received'
) as replies
from "threads" 
inner join "messages" 
on "messages"."thread_id" = "threads"."id" 
where "threads"."campaign_id" 
in ('campaign_uuid') 
group by "threads"."id"

Answer 1

您可以进行窗口计数：

select "threads".*, 
count("messages"."extra"->'opens') as opens, 
count("messages"."extra"->'clicks') as clicks, 
count(*) 
    filter(where "messages"."direction"='received') 
    over(partition by "threads"."id") as replies
from "threads" 
inner join "messages" 
on "messages"."thread_id" = "threads"."id" 
where "threads"."campaign_id" 
in ('campaign_uuid') 
group by "threads"."id"