Mysql根据条件计算列值

Question

我有一个表格，列有day ， month ， year ， total_payments 。 我必须根据days ， months ， years计算total_payments 。

我该如何计算价值？

我在想代码：

select 
    month, year, sum(total_payments) 
from 
    webassignment.subscription_stats 
group by 
    day;

select 
    month, year, sum(total_payments) 
from 
    webassignment.subscription_stats 
group by 
    month;

select 
    month, year, sum(total_payments) 
from 
    webassignment.subscription_stats 
group by 
    year;

但它不会返回正确的答案。 我想计算total_payments daywise，monthwise，yearwise。 请帮我找到价值观。

样本输入：

Day Month   Year    Total_payments
10  01      2008    10
10  01      2008    20
11  02      2008    10
10  03      2010    10

输出：

日间：

day month year total_payments
-----------------------------
10  01    2008 30
11  02    2008 10
10  03    2010 10

月份和年份相同

Answer 1

一种方法可以是在联盟上使用，以显示基于不同逐级的不同结果

  select day, month,year,sum(total_payments) 
  from webassignment.subscription_stats group by day, month,year
  union 
  select null, month,year,sum(total_payments) 
  from webassignment.subscription_stats group by month,year
  union 
  select null, null ,year,sum(total_payments) 
  from webassignment.subscription_stats group by year
  order by year, month, day

你提供的样本应该足够了

  select day, month,year,sum(total_payments) 
  from webassignment.subscription_stats group by day, month,year
  order by day, month,year

Answer 2

您可以使用GROUP BY WITH ROLLUP按年，月和日获得总计：

SELECT
    `Year`,
    `Month`,
    `Day`,
    SUM(`Total_payments`) as `Totals`
FROM `webassignment`.`subscription_stats`
GROUP BY `Year`,`Month`,`Day` WITH ROLLUP;

如果您想要年，月和日的个人查询：

按年份：

SELECT
    `Year`,
    SUM(`Total_payments`) as `Totals`
FROM `webassignment`.`subscription_stats`
GROUP BY `Year`
ORDER BY `Year;

按月：

SELECT
    `Year`,
    `Month`,
    SUM(`Total_payments`) as `Totals`
FROM `webassignment`.`subscription_stats`
WHERE `Year` = 2017
GROUP BY `Year`,`Month`
ORDER BY `Year`,`Month`;

白天：

SELECT
    `Year`,
    `Month`,
    `Day`,
    SUM(`Total_payments`) as `Totals`
FROM `webassignment`.`subscription_stats`
GROUP BY `Year`,`Month`,`Day`
ORDER BY `Year`,`Month`,`Day`;