Question

我有三张这样的表

CREATE TABLE  `money`.`categories` (
  `ID` bigint(20) unsigned NOT NULL AUTO_INCREMENT,
  `Title` text NOT NULL,
  PRIMARY KEY (`ID`)
)

CREATE TABLE  `money`.`expenditure` (
  `ID` bigint(20) unsigned NOT NULL AUTO_INCREMENT,
  `Purpose` text NOT NULL,
  `Amount` bigint(20) unsigned NOT NULL,
  `Date` datetime NOT NULL,
  `CategoryID` bigint(20) unsigned NOT NULL,
  PRIMARY KEY (`ID`),
  KEY `FK_expenditure_1` (`CategoryID`),
  CONSTRAINT `FK_expenditure_1` FOREIGN KEY (`CategoryID`) REFERENCES `categories` (`ID`)
)

CREATE TABLE  `money`.`income` (
  `ID` bigint(20) unsigned NOT NULL AUTO_INCREMENT,
  `Source` text NOT NULL,
  `Amount` bigint(20) unsigned NOT NULL,
  `Date` datetime NOT NULL,
  PRIMARY KEY (`ID`)
)

实际上并不复杂。非常简单。

我有三个查询要查找

特定月份的收入总和：
select sum(amount) tot_inc from money.income ic where month(ic.date) = 02;
特定月份的支出总和：
select sum(amount) tot_exp from money.expenditure ex where month(ex.date) = 02;
特定类别特定月份的支出总和：
select sum(amount) tot_exp from money.expenditure ex where month(ex.date) = 02 and ex.categoryid = 3;

我有两个问题：

如何找出已经消失的总收入占特定月份总支出的百分比。基本上我想从查询1和2中找出（100 * tot_exp / tot_inc）但是如何在查询中写出来？
在此基础上，我想了解每个类别的支出在特定月份的贡献百分比。我知道它是分组和聚合和/或数学函数的组合，但我甚至无法开始可视化查询的编写方式。我怎样才能得到这些数字？

Answer 1

SELECT 
(100*(SELECT SUM(amount) tot_inc FROM money.income ic WHERE month(ic.date) = "02")/SUM(amount)) AS "Result"
FROM expenditure e 
WHERE MONTH(ex.date) = "02"
GROUP BY CategoryID
HAVING result > 10

我认为会是这样的

如何按类别分组，然后找到收入的百分比？

1 个答案: