Question

我有两个表，account_subscriptions和order_item，我写了这个查询：

Select a1.accounts_id,sum(a2.quantity * a2.unit_price) as MRR
from account_subscriptions a1 
inner join order_item a2 on a1.subscription_id = a2.account_subscriptions_id 
group by a1.accounts_id;

使用此代码，我可以找到total_bill作为MRR及其相应的account_id。但是现在我想将它放在一个名为summary的现有表中，其中已经有一些列以及account_id和MRR列为空。

我想将我从查询中得到的MRR值放入MRR列，并与summary table和account_subscriptions表的相应account_id相匹配。

Answer 1

尝试更新，而不是插入：

with c as (
Select a1.accounts_id,sum(a2.quantity * a2.unit_price) as MRR
from account_subscriptions a1 
inner join order_item a2 on a1.subscription_id = a2.account_subscriptions_id 
group by a1.accounts_id
)
update summary s set MRR = c.MRR 
from c
where c.accounts_id = s.accounts_id

更新核对您的评论，并将其打包为功能使用

create function fn_name_here() returns int as
$$
begin
    with c as (
    Select a1.accounts_id,sum(a2.quantity * a2.unit_price) as MRR
    from account_subscriptions a1 
    inner join order_item a2 on a1.subscription_id = a2.account_subscriptions_id 
    group by a1.accounts_id
    )
    update summary s set MRR = c.MRR 
    from c
    where c.accounts_id = s.accounts_id;
return 0;
end;
$$ language plpgsql
;

请开始阅读和练习SQL和/或plpgsql - 只是将代码包装在函数中没有多大意义。内部没有逻辑......

postgresql join和insert

1 个答案: