Question

这可能很简单，但我无法弄清楚。

我有两个表中的数据 - 1）贷款2）还款。我被要求根据我们当前的投资组合制作一份报告来计算每个季度的预期余额。

所以我采取的方法是采用贷款表中所有余额的总和（给出我们的当前余额）和偿还表中所有预期付款的总和，以及按QUARTER（duedate）和YEAR（duedate）分组）减去，以便我们可以预测当时贷款的回报。

我复制下面的代码：

select sum(la.PRINCIPALBALANCE) - due.due as balance 
    ,due.q
    ,due.y
from loans la
join (select 
        PARENTACCOUNTKEY
        ,sum(principaldue) as due
        ,quarter(duedate) as q
        ,year(duedate) as y
    from repayment 
    group by quarter(duedate),year(duedate)) as due 
on la.encodedkey = due.parentaccountkey
group by due.q ,due.y

如果我们有以下简化数据，我希望看到的是：

贷款：

ID        principalbalance  
1         2500  
2         2500

支付：

Parentaccountkey    principaldue      duedate  
1                   500               Q1  
1                   500               Q2   
1                   500               Q3  
2                   100               Q1  
2                   100               Q2  
2                   100               Q2

我希望我的结果表显示以下内容

Q1     4400 (which is the 2500 + 2500 principalbalance starting point, minus the 500 + 100 due in that month.
Q2     3800 (the 2500 + 2500, minus the 500 + 100 for Q1 and minus 500 + 100 for Q2)
Q3     3200 (the 2500 + 2500 minus the amounts for Q1, Q2 & Q3)

Answer 1

编写一个子查询，用于计算每个季度principaldue的运行总计。然后将其与计算总余额的查询相结合，以便每个季度减去它。

SELECT duedate, total - running_due AS balance
FROM (SELECT a.duedate, SUM(b.principaldue) AS running_due
      FROM (SELECT DISTINCT duedate
            FROM repayments) AS a
      JOIN repayments AS b ON b.duedate <= a.duedate
      GROUP BY a.duedate) AS x
CROSS JOIN (SELECT SUM(principalbalance) AS total
            FROM loans) AS y
ORDER BY duedate

还有其他方法可以计算运行总计，您可以搜索它们并将子查询替换为数据库中最有效的子查询。

MySQL创建查询以根据两个表中的日期计算未来余额

1 个答案: