Question

大家好，我在回答这个问题时遇到了问题...

对于每个账户清单，事件数量，存款金额，提款金额以及存款和取款金额。我遇到了这背后的逻辑问题。我一直在想，这需要一个循环，但我知道这不正确......有没有人知道如何解决这个问题？

Database/Table structure: 
Account (accountNo, ownerNo, balance)
Owner (ownerNo, firstName, lastName)
Event (id, accountNo, event, amount, eventDate)

我尝试过的代码：

SELECT COUNT(event) AS 'Account 1 number of events'
FROM Event
WHERE accountNo = 1

然后从那里继续列出帐户 - 但是对于可重用性而言，这对每个帐户都不起作用且效率不高。

Answer 1

试试这个：

select
  account.accountNo,
  count(1) as number_of_events,
  sum(case when event.amount > 0 then event.amount else 0 end) as deposits,
  sum(case when event.amount < 0 then event.amount else 0 end) as withdrawals,
  sum(event.amount) as sum_deposits_withdrawals
from
  account
inner join
  event on
  event.accountNo = account.accountNo
group by
  account.accountNo

如何在不使用循环的情况下列出sql中的每个帐户信息和总和

1 个答案: