SQL Server累积总和(按组)

本文介绍了SQL Server累积总和(按组)的处理方法，对大家解决问题具有一定的参考价值，需要的朋友们下面随着小编来一起学习吧！ 问题描述

我有一个这种格式的表(SQL Server 2005):

I have a table (SQL Server 2005) of this format:

虚拟身份证，注册日期，商品ID，数量，价格

，我想添加一个新列( cumulative )，该列按date_registered计算每个item_id订单的累计总数，如下所示:

and I want to add a new column (cumulative) which calculates the cumulative totals of each item_id order by date_registered as shown:

dummy_id date_registered item_id quantity price cumulative 1 2013-07-01 100 10 34.5 10 2 2013-07-01 145 8 2.3 8 3 2013-07-11 100 20 34.5 30 4 2013-07-23 100 15 34.5 45 5 2013-07-24 145 10 34.5 18

先感谢

推荐答案

在SQL Server 2005中，我将使用相关子查询来做到这一点:

In SQL Server 2005, I would do this using a correlated subquery:

select dummy_id, date_registered, item_id, quantity, price, (select sum(quantity) from t t2 where t2.item_id = t.item_id and t2.date_registered <= t.date_registered ) as cumulative from table t;

如果您确实要将其添加到表中，则需要更改表以添加列，然后进行更新.如果表具有插入和更新，则需要添加触发器以使其保持最新状态.通过查询获取它绝对容易.

If you actually want to add this into a table, you need to alter the table to add the column and then do an update. If the table has inserts and updates, you will need to add a trigger to keep it up-to-date. Getting it through a query is definitely easier.

在SQL Server 2012中，您可以使用以下语法执行此操作:

In SQL Server 2012, you can do this using the syntax:

select dummy_id, date_registered, item_id, quantity, price, sum(quantity) over (partition by item_id order by date_registered) as cumulative from table t;