查询以获取列总数并减去 MySQL答案

【问题标题】：Query to get column totals and Subtract MySQL查询以获取列总数并减去 MySQL
【发布时间】：2018-09-06 15:14:10
【问题描述】：

我有一个事务表

我可以使用这些查询分别按属性获取所有借方和贷方交易总额

SELECT property, SUM(amount) as creditamount FROM transactions WHERE transactions.type="CREDIT" GROUP BY property    

SELECT property, SUM(amount) as debitamount FROM transactions WHERE transactions.type="DEBIT" GROUP BY property

我很难在一个查询中完成这两个查询，以便我可以减去每行的贷方金额和借方金额并根据属性列出它

我尝试使用子查询，但返回多行。

有什么方法可以实现吗？

【问题讨论】：

标签： mysql database select transactions subquery

【解决方案1】：

条件聚合可能是您正在寻找的。p>

SELECT property, 
 SUM(case when type = 'Credit' then amount else 0 end) as creditamount,
 SUM(case when type = 'Debit' then amount else 0 end) as debitamount,
 SUM(case when type = 'Credit' then amount else 0 end) -
 SUM(case when type = 'Debit' then amount else 0 end) as  diff
 FROM transactions 
 GROUP BY property

【讨论】：

【解决方案2】：

使用自加入

select debitamount , creditamount
from (select sum(amount) income
     from  transactions 
     WHERE transactions.type="CREDIT"  
     GROUP BY property) i
JOIN (select sum(rate) debitamount 
     from transactions 
     WHERE transactions.type="DEBIT" 
     GROUP BY property) e

参考this question

【讨论】：