sql與另一個表格計算多個記錄

Question

我在這裏有兩個表格。我想要的是在這兩個表格內計算（添加）數量和平衡。但困難在於交易表中的兩個account_no是相同的（A-102）。那麼如何在transactions.account_id = account.account_no = A-102時將amount加到balance？

我所做的是：

select account_no, balance + (
           select t.amount 
           from transactions t 
           where t.account_no = 'A-222') 
    from b_account 

    where account_no = 'A-222'; 

這種方法僅適用A-305和A-222。 如果我寫這樣的，它不會工作..

select account_no, balance + (
           select t.amount 
           from transactions t 
           where t.account_no = (
                select t.account_no 
                from b_account ba, transactions t 
                where ba.account_no = t.account_no 
                )  
          ) 
from b_account 
where account_no = (select t.account_no 
        from b_account ba, transactions t 
        where ba.account_no = t.account_no); 

任何幫助的感謝！先進

Answer 1

您可以通過帳號group和sum所有金額，然後將結果加入帳戶表。試試這個

with cte as 
(
select account_no, SUM(t.amount) amount 
from transactions t 
--where t.account_no = 'A-222' 
group by account_no 
) 

Select a.account_no, balance + coalesce(b.amount,0) new_balance 
from b_account a 
left outer join cte b on a.account_no = b.account_no 
--where a.account_no = 'A-222'