如何在GROUP BY中的多个条件上汇总列

Question

我试图返回一份账户清单,包括余额,结果和收入

Account            Transaction
-------            -----------
AccountID          TransactionID
BankName           AccountID
Locale             Amount
Status

这是我现在拥有的.有人可以解释我哪里错了吗？

select
    a.ACCOUNT_ID,
    a.BANK_NAME,
    a.LOCALE,
    a.STATUS,
    sum(t1.AMOUNT) as BALANCE,
    sum(t2.AMOUNT) as OUTCOME,
    sum(t3.AMOUNT) as INCOME
from ACCOUNT a
left join TRANSACTION t1 on t1.ACCOUNT_ID = a.ACCOUNT_ID
left join TRANSACTION t2 on t2.ACCOUNT_ID = a.ACCOUNT_ID and t2.AMOUNT < 0
left join TRANSACTION t3 on t3.ACCOUNT_ID = a.ACCOUNT_ID and t3.AMOUNT > 0
group by a.ACCOUNT_ID, a.BANK_NAME, a.LOCALE, a.[STATUS]

UPDATE

根据下面的评论更正了t2左连接语法.

我期待的输出有望从问题中显而易见.对于6个帐户,SQL应返回6个帐户及其帐户的余额,收入和结果.

我提供的SQL问题是数字错误!根据评论,我认为问题源于连接多次,这是错误地汇总金额.

Answer 1

既然你没有告诉我们出了什么问题(也就是描述你得到的行为,除了描述你期望的行为)之外,很难说在哪里,但有几种可能性.尼尔指出一个.另一个原因是,由于您在事务表上加入了三次,因此您将事务与事务配对并重复进行.相反,一次加入事务表并更改Amount列总结的方式.

Select
    a.ACCOUNT_ID,
    a.BANK_NAME,
    a.LOCALE,
    a.STATUS,
    sum(t.AMOUNT) as BALANCE,
    sum((t.AMOUNT < 0) * t.AMOUNT) As OUTGOING,
    sum((t.AMOUNT > 0) * t.AMOUNT) As INCOMING
From ACCOUNT a
Left Join TRANSACTION t On t.ACCOUNT_ID = a.ACCOUNT_ID
Group By a.ACCOUNT_ID, a.BANK_NAME, a.LOCALE, a.[STATUS]

您可以使用CASE表达式作为乘法的更可读的替代方法:

Select
    a.ACCOUNT_ID,
    a.BANK_NAME,
    a.LOCALE,
    a.[STATUS],
    sum(t.AMOUNT) As BALANCE,
    sum(CASE WHEN t.AMOUNT < 0 THEN t.AMOUNT ELSE 0 end) As OUTCOME,
    sum(CASE WHEN t.AMOUNT > 0 THEN t.AMOUNT ELSE 0 end) As INCOME
From ACCOUNT a
Left Join [TRANSACTION] t On t.ACCOUNT_ID = a.ACCOUNT_ID
Group By a.ACCOUNT_ID, a.BANK_NAME, a.LOCALE, a.[STATUS]

Answer 2

你的意思是:

select 
    a.ACCOUNT_ID, 
    a.BANK_NAME, 
    a.LOCALE, 
    a.STATUS, 
    sum(t1.AMOUNT) as BALANCE, 
    sum(CASE WHEN t2.AMOUNT < 0 THEN t2.Amount ELSE 0 END) as OUTCOME, 
    sum(CASE WHEN t3.AMOUNT > 0 THEN t3.Amount ELSE 0 END) as INCOME 
from 
    ACCOUNT a 
    left join TRANSACTION t1 on t1.ACCOUNT_ID = a.ACCOUNT_ID 
    left join TRANSACTION t2 on t2.ACCOUNT_ID = a.ACCOUNT_ID
    left join TRANSACTION t3 on t3.ACCOUNT_ID = a.ACCOUNT_ID
group by 
    a.ACCOUNT_ID, a.BANK_NAME, a.LOCALE, a.[STATUS]