如何在新列中添加联合所有结果

Question

我想查询每个设备的总数：数量 * 成本。

现在我想做一个 MySQL 查询，我在其中创建了一个执行以下操作的临时列：

Total - Total of Totals
80    -  80
90    -  170
100   -  270

现在我有这样的代码：

Select total
from equipment
UNION ALL
select sum(total) from equipment;

这给出了总计下面的总计。我想把它分开，然后在它旁边依次做。

Answer 1

使用GROUP BY和ROLLUP:

SELECT id, SUM(quantity * costs) AS total
FROM equipment
GROUP BY id WITH ROLLUP;

在结果集的底部会出现一条NULL作为id的记录，其总和将超过所有组。

Answer 2

你似乎想要一个 window 函数，像这样：

select (quantity * costs) as total,
       sum(quantity * costs) over (order by quantity * costs) as running_total
from equipment;

我实际上希望您现有的总数是聚合的结果。你的问题不清楚是什么，但你可以使用 window 函数和聚合函数：

select sum(quantity * costs) as total,
       sum(quantity * costs) over (order by sum(quantity * costs)) as running_total
from equipment
group by <something>

Answer 3

在 Mysql 8 中，您可以使用 window 函数

WITH CTE AS (
SELECT
   quantity * costs as total as total
FROM 
equipment)
    select
      total,
      sum(total) over (order by total) as cumulative_sum
    from CTE;

如何在新列中添加联合所有结果

How to add a union all result in a new column

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